UK Government Policy and the Transition to a Circular Nutrient Economy

Abstract

The “circular economy” is an increasingly influential concept linking economic and environmental policy to enable sustainable use of resources. A crucial although often overlooked element of this concept is a circular nutrient economy, which is an economy that achieves the minimization of nutrient losses during the production, processing, distribution, and consumption of food and other products, as well as the comprehensive recovery of nutrients from organic residuals at each of these stages for reuse in agricultural production. There are multiple interconnecting barriers to transitioning from the current linear economic system to a more circular one, requiring strongly directional government policy. This paper uses interpretive policy analysis to review six UK government strategies to assess their strengths and weaknesses in embracing nutrient circularisation. Our analysis highlights the acute underrepresentation of the circular nutrient economy concept in these strategies as well as the potential to reorient the current policy towards its development. We find significant barriers to transition presented by ambiguity in key policy terms and proposals, the use of inappropriate indicators, the lack of a systematic approach to key sustainability objectives, and the presence of a “techno-optimist imaginary” throughout the strategies. We develop these findings to make recommendations to help integrate definitions, objectives, and activities across the policy domains necessary for the operational development of a circular nutrient economy.

1. Introduction

In 2022, it is clear that the operation and expansion of human economic activity has had severely detrimental effects on the planet’s environment, threatening its capacity to sustain natural cycles, healthy ecosystems, human prosperity, and perhaps even human survival [1]. In the face of multiple crises of climate [2], biodiversity and habitat loss [3], and resource depletion [4], there is an urgent need to adapt our current patterns of economic activity to more sustainable approaches. The “circular economy” (CE) is an increasingly influential concept linking economic and environmental policy, which promises just such a pathway towards sustainability [5]. Developing a CE is increasingly acknowledged as a priority within academia, policymaking, and industry, dominating discussion about how best to disrupt unsustainable patterns of economic activity, especially in Europe and Asia [6].

Developing a CE involves shifting from our current linear economic model based on extraction, production, consumption, and disposal to a closed-loop system where waste is “designed out” by maximising reuse, recovery, recycling, and value retention of products, materials, and their components [7]. Where the linear economic model is degenerative (i.e., material resources and energy are lost from the system at every stage, and end products in turn become waste), the CE is intentionally regenerative (i.e., as much as possible, the materials that would previously have been lost to the system as waste are returned to it as resources, thus continually replenishing the system’s ability to support itself) [8]. As well as addressing critical problems of resource scarcity and environmental degradation, moving to a CE is also essential to addressing climate change and achieving low-carbon economies [9].

One crucial but often overlooked element of the regenerative nature of a CE is the return of nutrients to land (e.g., recycling of biowastes and renewable fertilisers derived from them) in ways which maintain soil health and fertility and rebuild natural capital [8,10]. This is vital to avoid (1) nutrient deficits in agricultural land where they are essential for food production and (2) nutrient escape and accumulation as air, water, and soil pollution, with significant consequences for ecosystem (and human) health [11,12]. Nutrients are added in inorganic fertilisers and supplements to animal feed and imported food and are lost through a variety of system processes (e.g., leaching and runoff from the land surface, accumulation in agricultural soils, food wastage during production, processing and consumption, municipal and industrial effluent discharge, and waste to landfill), layering a linear economic system over natural nutrient cycles. Interference with the natural cycles of the primary nutrients nitrogen (N) and phosphorus (P) is already estimated to have breached what Swedish earth scientist Rockström and colleagues describe as a “safe operating space” for humanity [1,13]. N and P are also intimately linked to carbon (C) cycles, with excess N and P having potentially highly negative impacts on primary productivity, food web dynamics, and C sequestration [14,15].

These effects mark the culmination of system intensification that began with the geographical differentiation of livestock and arable farming, separating farm systems that produced nutrients from farm systems that required them and with rapid urbanisation during the industrial revolution which separated the locations of food production and consumption. Such developments broke the chain of recycling nutrients from human, animal, and food wastes back to the land. They were further amplified by the industrialisation of agriculture, particularly the mass production of inorganic fertilisers in global supply chains, causing what environmental sociologists and political economists have termed a “metabolic rift”, a rupture under capitalism in the relation between human economies and the biophysical systems that they depend upon [16,17,18,19].

Therefore, while the recycling of nutrients must be a key component of a CE more generally, the environmental damage, food system vulnerability, resource insecurity, and market volatility associated with the current patterns of nutrient use and cycling within food systems have led to increasingly insistent calls for the specific development of a circular nutrient economy (CNE) [10,20,21,22]. A CNE may be broadly defined as “the reduction of nutrient losses–during agricultural production, processing, distribution, and consumption–along with comprehensive recovery of nutrients from organic residuals, for reuse in agricultural production” [23]. However, as with CE more widely, we recognise that there is not a commonly agreed upon definition and that this can be problematic for its operational implementation [24]. Nevertheless, as an example of the traction the issue is gaining amongst policymakers, the European Union recognised the centrality of returning nutrients to land in their 2015 Circular Economy Action Plan, acknowledging that “[r]ecycled nutrients are a distinct and important category of secondary raw materials” [25] (pp. 3, 11). Two of the plan’s four key resource stream-specific proposals relate to fertilisers and wastewater, and one of its two sectoral priority areas is food waste, all of which are central to the recycling of nutrients. This includes P as a “critical raw material” alongside rare earth elements and precious metals [25] (p. 15).

A CNE that could begin to repair this rift would consist of both biological and chemical cycles that capture excess nutrients that are lost from the system as waste at different stages of production, processing, and consumption and feed them back in as inputs, as illustrated in Figure 1. This would reduce reliance on the unsustainable and unreliable extraction and production of raw materials, contribute to food security and market stabilisation, and reduce harmful pollution.

Whereas it is acknowledged that there is excessive loss and waste within food systems (the orange column above), nutrients are currently recycled via biological (green) pathways, namely the application of organic materials (e.g., manure, slurry, compost, or sewage sludge) to agricultural soils which supplies a combination of organic matter and nutrients, both of which are essential for soil health [26]. The chemical (blue) nutrient cycle is predominantly linked to residues of energy generation from biomass (normally ashes and digestates) and to technologies for extracting selected nutrients from a waste matrix (e.g., struvite removal from wastewater) [27,28]. There is increasing interest in exploring more opportunities to extract chemicals from organic waste to overcome some of the barriers to their use as secondary nutrient sources [10,29]. However, this risks exacerbating the existing decoupling of nutrient flows from the return of organic matter and carbon to the soil, depleting the soil’s health and compromising its role as a carbon sink.

There are thus strong arguments for developing an economy-wide CE (that must incorporate CNE as an integral element in order to succeed) and specific arguments for developing a CNE in its own right. However, shifting a linear economic system to a circular one signifies radical transformation of path-dependent, “locked-in” sociotechnical systems of consumption and production [30,31]. Achieving such a transition will require strong, clear, and consistent government policy to overcome multiple barriers to transition [32,33], especially under conditions in which the CE itself and the concepts that it relies on and relates to are capable of being interpreted in multiple ways [34].

Policy which seeks to drive transition to a CE will thus require clear and consistent interpretations that can be shared not just amongst policymakers but also policy “readers” (the agencies, businesses, NGOs, and individuals or public that will implement the policy). Policy analysis must “critically engage with the multiple meanings and futures of circularity” and the concepts with which it is associated [35] (p. 105). While multiple interpretations and understandings of policy are endemic and inevitable [36], a lack of clarity about policy objectives within the government would amplify the risk of significant gaps opening up between rhetoric, expectations, and practical implementation [37]. This could have severe consequences in a field that combines intractability, urgency, and importance. Given the pressing need to develop more sustainable economies, and if a CE is the route through which governments seek to achieve this sustainability, it will thus be vital for emerging policy at multiple levels across a complex range of domains to be clear, consistent, and strongly directive [38].

In this context, this paper takes the UK as a case study of an advanced industrial nation in which both the CE and the management of nutrients are increasingly becoming a focus of policy. It reviews six recent UK government strategies that have the most direct bearing on the development of a CNE as an essential component of a CE. The review was informed by an interpretive policy analysis approach. This approach enabled us to investigate the competing meanings within policy strategies relevant to a CNE, and the context and frames in which these strategies were set. The analysis was guided by the following questions:

• What is the stated purpose of each policy strategy?
• Do the strategies explicitly aim to contribute to the development of a CE?
• Do the strategies mobilise concepts that are constitutive for a CE?
• What role do nutrients and biological wastes (i.e., secondary nutrient sources) play in the strategies?
• What are the strengths and weaknesses of each strategy in relation to developing a CNE?

2. Materials and Methods

Interpretive policy analysis (IPA) seeks to put human meaning making and social realities at the heart of the analysis [39]. Rather than assuming that policy is an instrumentally rational response to a singular, objectively knowable set of circumstances, it is based on the presupposition that social realities (including policy issues) are subject to multiple possible interpretations. IPA enables a more adequate understanding of the likely success or failure of public policy [40,41].

Because meanings are relatively abstract and unobservable, IPA proceeds by identifying and analysing the more concrete and accessible “policy artefacts” which embody those meanings. These can consist of language, concepts, images, objects, or even actions. They are described as “policy artefacts” to emphasise that things that appear self-evident with obvious, pre-given singular meanings (e.g., the concept of “resource efficiency”) are in fact “made” through policy and can be “made” in different ways. They are thus not passive or neutral but have effects in terms of making audiences (e.g., policy makers and citizens) think and act in particular ways in relation to those artefacts [39].

In this paper, we focus on the language inscribed in the six UK strategies identified as being most relevant to the development of a CNE due to their collective coverage of the policy issues of economic development, resource use, agriculture and soils, production and use of fertilisers, production and management of waste, management of air and water pollution, environmental protection, and climate change. Our method of analysis can be summarised as follows, and we provide more detail in the paragraphs below:

• Identify key economic and environmental strategies;
• Identify relevant policy artefacts and develop a list of keywords;
• Search each strategy for keywords;
• Identify the subsections in each strategy in which keywords appear;
• Close reading of identified subsections in each strategy to understand the context, framing, and interpretation of keywords;
• Close reading of sections in which the identified subsections appear to understand the context, framing, and interpretation of proposals associated with the keywords;
• Identify any new keywords arising from inductive analysis, and repeat steps 3–5 for any new keywords;
• Read each strategy as a whole to understand the extent of penetration of CNE-related concepts;
• Comparison of context, framing, and interpretation of identified policy artefacts across strategies at the subsection, section, and whole document levels;
• Assessment of absolute and relative strengths and weakness of individual strategies in relation to a CNE;
• Assessment of strengths and weakness of strategies as a bundle in relation to a CNE.

The six strategies identified were the following:

• The Clean Growth Strategy [42];
• The Industrial Strategy [43];
• The 25-Year Plan for the Environment [44];
• The Bioeconomy Strategy [45];
• The Resources and Waste Strategy [46];
• The Clean Air Strategy [47].

These strategies represent a formal expression of UK government policy across the specified fields, encompassing extant policy initiatives alongside proposals for legislation and other action. They therefore make up the national policy framework within which a CNE may (or may not) develop and which will guide, foster, or hinder such development. Within these strategies, we identified the policy artefacts that are significant carriers of meaning associated with this issue, producing the following list of keywords associated with nutrient use or a circular economy: circular economy, waste reduction, reuse, recovery, recycle, resource efficiency, resource productivity, nutrient, soil, agriculture, farming, fertiliser, organic, phosphorus, nitrogen, wastewater, sewage, food, slurry, anaerobic digestion, organic waste, biowaste, and food waste. We identified (1) every incidence in each strategy where these keywords were deployed, (2) clusters of keywords in particular sections, and (3) the sections where the keywords associated with each framing (i.e., nutrients and CE) co-occurred.

The documents were reviewed through iterative cycles of detailed analysis to assess their treatment of CNE and CNE-relevant policy artefacts and to explore the different interpretations and framings which contextualise them across the strategies. For each strategy, the sections in which keywords occurred were subject to close reading, followed by scrutiny of the document as a whole to better understand the context in which the policy artefacts were located. In the initial analysis, “clean growth” emerged inductively as an additional highly significant CE-relevant policy artefact across the strategies, to which subsequent analysis paid particular attention. A comparison across documents was then carried out. Each previously identified section was then revisited in light of the wider context provided by the full set of documents.

To understand the consequences of a policy requires an understanding of the “local” expert knowledge and framings that policy actors in different interpretive communities (groups that share cognitive, linguistic, and cultural practices and understandings) bring to the interpretation of policy issues [48]. IPA holds that the meaning of a policy does not lie simply in the authors’ intentions, in the policy text, or in the various interpretations that different actors will make of the policy but in the interactions between these three elements. We took the authors of each strategy to represent different interpretive communities within the policymaking community which contextualise, frame, and imbue policy artefacts with different meanings through the production of policy texts. Each policy text will have a diverse range of audiences beyond the policymaking community that will engage with it and generate new interpretations in turn. However, this analysis focuses on the comparison of meanings within and between the different interpretive communities that produced the strategies.

We analysed the discourse of these communities, namely how they talked about and represented the policy issue and artefacts, and we identified the key absences within this discourse. We focused on the multivalent framings within the texts themselves, clarifying specific meanings communicated through particular artefacts and highlighting unresolved ambiguities amongst the framings. Different framings (and absences) emphasise and marginalise different elements and meanings of the issue, shaping perceptions, understandings, and hence actions. We identified the meanings that were in conflict or tension between these groups and explored the implications of these conflicts and tensions, including on the implementation of policy by a variety of external policy-relevant interpretive communities (e.g., public agencies, businesses, entrepreneurs, NGOs, and publics). We considered these issues in the context of the likely contribution that UK government policy might make to enhancing environmental sustainability and reducing resource use through supporting the development of a CNE. We used this analysis to provide a platform for intervention, propose a reframing of the policy issue, and reformulate the policy artefacts in order to produce a policy that is more likely to succeed in driving a transition to a CNE.

3. Results

3.1. CE and CNE as Features of UK Government Policy

The headline results of the analysis are summarised in

Table 1. Summary of results.

	Clean Growth Strategy (CGS) (October 2017)	Industrial Strategy (November 2017)	25 Year Plan for the Environment (January 2018)	Bioeconomy Strategy (December 2018)	Resources and Waste Strategy (RWS) (December 2018)	Clean Air Strategy (January 2019)
Summary aim and purpose of strategy	Grow the economy while reducing greenhouse gas emissions by meeting climate change commitments at the lowest possible net cost and maximising social and economic benefits from the low-carbon transition (p. 5, p. 47)	Increase productivity and earning power by investing in and encouraging innovation, education, and skills development in infrastructure, a business-friendly environment and local areas across the UK (pp. 10–11)	Achieve clean air, clean and plentiful water, thriving plants and wildlife, reduced risk of harm from environmental hazards, more sustainable use of natural resources, enhanced beauty, heritage, and engagement with nature, mitigate and adapt to climate change, minimise waste, manage exposure to chemicals, and enhance biosecurity (p. 23)	Promote the use of biological resources to replace fossil resources, create new solutions in agri-food, chemicals, materials, energy, and fuel production, health and the environment that are economically and environmentally sustainable and resource efficient (p. 9)	Preserve material resources by minimising waste, promoting resource efficiency, and moving towards a circular economy, minimise environmental damage by reducing and managing waste safely and by tackling waste crime (p. 7)	Tackle all sources of air pollution, making our air healthier to breathe, protecting nature, and boosting the economy (p. 6)
Presence of CE as policy artefact	Passing references to two external documents (p. 105, p. 136)	Two linked “inserts” in “Infrastructure” chapter (p. 148, p. 150)	Statement that Industrial Strategy promotes moving towards a CE (p84)	Three references to plastics (p. 10, p. 18, p. 24), one remark about general CE opportunities from the bioeconomy (p. 15), and a CE diagram (p. 16)	Emphasised throughout as both end point and process	None
Presence and context of CE-relevant policy artefacts	CE-relevant artefacts largely confined to “Natural resources” sub-section of Chapter 4, “Sectors” (pp. 102–112, esp. pp. 108–109) and a paragraph on process, resource, and material efficiency (p. 68)	CE-relevant artefacts are confined to two “inserts” (p. 148, p. 150) and a paragraph on resource productivity (p. 161) in the “Infrastructure” chapter	CE-relevant artefacts highlighted in exec summary (p. 9, p. 10, p. 13), introduction (p. 16, p. 21, p. 23, p. 27), and in the introduction to and first section of Chapter 4 “Increasing resource efficiency and reducing pollution and waste” (pp. 83–94)	CE-relevant artefacts are concentrated in the exec summary (pp. 11–12), introduction (p. 18, pp. 20–22), and “Infrastructure” (pp. 35–37) chapters, with minor mentions in chapters on places (p. 47) and business environment (p. 42)	CE cited as a goal and a guide throughout. Includes specific measures to increase resource productivity and efficiency, extend product lifespans, reduce waste, and increase reuse, recovery, and recycling.	References to efficiency relate to energy use (e.g., p. 8, p. 27, p. 40, p. 42), and nutrient use (pp. 69-71). Other CE-relevant artefacts are absent.
Framing of nutrients and related policy artefacts	Fertilisers and soil quality identified as opportunities for innovation (including waste-based fertilisers) (pp. 109–110). Low-emission fertilisers encouraged (p. 106). Commits to innovation and support in agriculture to deliver better environmental outcomes (p. 53, pp. 103–105).	CE “inserts” imply return of nutrients to land as part of CE (p. 148, p. 150). No reference to nutrients beyond “inserts”. Commits in broad terms to high-efficiency, more sustainable agriculture, and supporting research (p. 47, p. 75, p. 188).	Emphasis on pollution risk from nutrient loss (pp. 38–39, p. 99). Commitment to improve soil health (p. 43). Broad commitments to sustainable food production and productivity growth in agriculture while putting the environment first (p. 7, p. 9, pp. 36–37).	No mention of nutrients, fertilisers, or soils. Generalised commitment to more sustainable, productive, and resilient agriculture (p. 10). Inclusion of agriculture in the bioeconomy (p. 15, p. 20, p. 52).	Food waste that cannot be treated higher up the waste hierarchy should be anaerobically digested (AD) and digestate applied to soil to provide nutrients and organic matter (pp. 71–72, pp. 103–104). Notes that AD can also be used for other organic waste streams (p. 71). Garden waste can be composted (p. 72).	Emphasis on pollution risk from nutrient loss (pp. 67–73). Benefits of making better use of nutrient resources as the corollary of pollution reduction are mentioned in passing rather than integral to the strategy (p. 37, p. 69).
Framing of biological wastes	Utilising food and biowaste mentioned in context of ‘zero avoidable waste by 2050′ (p. 54, p. 108). Potential for fuel (p. 84, p. 92) and fertiliser (p. 110) production from biowastes mentioned. AD digestate addressed as waste management problem (rather than nutrient source) (p. 53, p. 111).	No explicit reference beyond CE ‘inserts’. Commits broadly to reduce food waste (p. 148, p. 188) develop markets for waste materials and promote use of precision technologies to reduce agricultural waste (p. 75, p. 161)	Manures and slurries treated primarily as pollution risk (pp. 38–39, p. 99). Food waste discussed in terms of reduction and redistribution (pp. 89–90). Wastewater addressed as pollution management problem (p. 96).	Potential to use biowastes to produce fuel, chemicals, pharmaceuticals, materials and energy is identified, but not to return nutrients to land/produce fertiliser or soil conditioner (p. 35).	AD digestate treated as both risk and resource (pp. 71–72). Digestate and compost need quality control to provide farmers with a high-quality product (p. 72, p. 106). Focuses on food waste (pp. 98–109). Commits to policy reviews to support recycling biowastes and finding synergies with renewable energy using AD to manage farm waste and garden waste composting (p. 72). Other uses for biowastes acknowledged, but nutrient recycling given primacy (p. 130).	Slurry, manure, and AD digestate considered mainly in terms of pollution risk rather than resource value (pp. 67–73) (although “nutrient-rich” nature of digestate acknowledged (p. 73)). Additional storage or production risks from these sources emphasised over those from inorganic fertilisers (p. 69, p. 71).
Potential strengths in relation to a circular nutrient economy	CE-related concepts are focused on agriculture and waste management. Exploring viability of recovering nutrients from waste identified as potential future opportunity.	The “inserts” explain and promote CE, including CNE, and set out measures that will contribute towards this. Commitment to “Transforming food production” as an ISCF programme.	Some areas draw on CE-relevant artefacts and would be best delivered through a shift to CE (especially elements of “Using and managing land sustainably” and “increasing resource efficiency and reducing pollution and waste”. Some commitments are suggestive of a shift towards a CE. Broad commitment to improving soil health.	General recognition of opportunities for CE in relation to bioeconomy. Emphasis on reducing waste and recognition of potential for waste streams to become resource streams.	Recognition that returning nutrients to soil is central to a CE. Primacy given to use of biowastes as nutrient and soil conditioners alongside other uses (energy, chemicals, materials, etc.). Strong support for AD, especially regarding food waste. Emphasis on quality and resource value of digestate and compost.	Commits to future fertiliser regulation which should inter alia prioritise use of organic fertilisers. Acknowledges status of AD digestate as source of nutrients as well as pollution risk.
Potential weaknesses in relation to a circular nutrient economy	Narrow definition of clean growth. CE-related concepts not mainstreamed throughout strategy and not within a context of driving circularity. Little detail on CNE actions (in comparison with other proposals). Competing uses for organic wastes (e.g., for fuel) emphasised.	Narrow definition of clean growth. Key policies and vision equally amenable to linear or CE. Aspirations of CE “inserts” not reflected in rest of strategy, with relevant artefacts absent from majority of strategy. Commitments to future research and action on agriculture are non-specific.	Goals and targets amenable to linear or CE. Specific actions only suggest shift to CE in relation to plastics. Competing uses for non-manure biowastes are highlighted (e.g., for biofuels or plastics) but not nutrient value. Minimising nutrient pollution risk not connected with maximising resource value. Emphasis on risks of organic fertilisers may inadvertently promote use of minerals.	Largely maintains linear economic model, substituting fossil resources for bio-based ones. References to using waste steams as resources exclude returning nutrients to land. General lack of reference to circularity other than in relation to plastics or to nutrients or soils. References to farming, food, and agriculture less specific than those to competing uses for biowastes (e.g., fuels, chemicals, or energy).	CNE focus largely confined to post-farm gate food waste, with no detailed engagement with other biowaste sources. AD and composting are the only mechanisms mentioned for returning nutrients to soil, ignoring potential of untreated waste stream and nutrient technologically recovered from biowastes.	Focus on pollution risks largely disconnected from resource value. Emphasis on risks of organic over inorganic fertilisers risks inadvertent pressure away from secondary nutrient sources towards inorganic fertilisers. Overall lack of engagement with CE ideas or the RWS.
Definition of “clean growth”	Growing national income while cutting greenhouse gas emissions (p. 5)	No specific definition but emphasises low-carbon technologies and the efficient use of resources (p. 42) and maximising the advantages for UK industry from the global shift to clean growth (p. 10, p. 14, p. 23, p. 34, p. 41)	No specific definition. References are sometimes ambivalent as to whether economic and environmental policies beyond cutting greenhouse gas emissions and growing national income are included (e.g., p. 9, p. 99, p. 145)	No specific definition. References are sometimes ambivalent as to whether economic and environmental policies beyond cutting greenhouse gas emissions and growing national income are included (e.g., p. 3, p. 33, p. 35, p. 45).	Growing national income whilst cutting greenhouse gas emissions. This includes increasing resource productivity and moving towards a more circular, low-carbon economy (and taking) comprehensive action on climate change, resource efficiency, and the environment (p. 130)	Growing national income whilst tackling air pollution, protecting the natural environment and cutting greenhouse gas emissions. Boosting productivity by improving air quality, using resources efficiently, and shifting to a low-carbon economy (p. 39)

, responding to the guiding research questions set out in the introduction. The numbers in the table refer to the page numbers in the specified strategy. The first row identifies the aim and purpose of each strategy to provide the overall framing of the strategy in the policy authors’ own words. The second row highlights direct references to a CE, showing the differing degrees to which developing a CE was communicated as an explicit aim. This remains peripheral at best in all strategies aside from the Resources and Waste Strategy, where it features strongly. However, there are other artefacts that are more mainstream in policy discourse through which a CE might be constituted, such as resource productivity and efficiency, waste reduction, reuse, recovery, and recycling. The third row details the occurrence and context of such artefacts, illustrating the extent to which each strategy could be interpreted as contributing to the achievement of a CE and the ways in which these artefacts were framed. For example, they are framed as mainly relating to natural resources in the Clean Growth Strategy (CGS) and to infrastructure in the Bioeconomy Strategy. They are strongly present throughout the Resources and Waste Strategy (RWS) and appear to be limited to a presentational device in the Industrial Strategy.

The fourth and fifth rows turn to the treatment of nutrients and biological waste, identifying first any explicit references, secondly the implicit references to their use and management (e.g., references to farming, agriculture, or soils), and the ways in which these policy artefacts were framed.

While nutrients and biological wastes feature across the strategies, their treatment differs widely. Broad commitments to more sustainable agriculture that could (but do not explicitly) incorporate CNE processes were relatively common across the strategies, but beyond the RWS, more specific references were infrequent (e.g., the CGS made one reference to developing waste-based fertilisers as a potential future innovation opportunity). Biological wastes were most frequently addressed as a problem of pollution risk and management, rather than as a secondary nutrient resource. Where biological wastes were considered a resource, it was more often in the context of supplying source material for fuels, chemicals, pharmaceuticals, or energy. Most surprisingly, the Bioeconomy Strategy made no mention at all of nutrients, fertilisers, or soils, and the 25-Year Environment Plan addressed wastewater solely as a pollution risk rather than a nutrient resource. The RWS, in contrast, drew attention to the ambiguity of biological (especially food) waste as both a pollution hazard and nutrient resource and emphasised the return of nutrients to land above other potential uses for biowastes.

In the sixth and seventh rows, based on an assessment of the extent to which the meanings embedded in CE- and CNE-relevant policy artefacts permeated the strategies or were restricted to specific contexts or framings, we made an overall assessment of the strengths and weaknesses of each strategy in relation to the development of a CNE. These highlighted that although a transition to a CNE would be compatible with each of the strategies, none of them contained policies that were clear, strong, or directive enough to require such a transition. In some cases, the greater emphasis on alternative uses for biological wastes and their treatment as risk rather than resource may actively militate against moving to a CNE. The RWS, while alone in strongly supporting a CE transition throughout and specifically advocating a CNE, focuses very narrowly in CNE terms on food waste and largely neglects other potential secondary nutrient sources.

Due to the apparent nature of “clean growth” as an organising concept across the strategies, and as a highly CE-relevant policy artefact, we also highlighted in the final row the different framings and meanings attributed to it in each strategy. This illustrates that while “clean growth” appears to be a common thread running throughout the strategies, the meanings which it carries (and therefore the actions which it may produce) vary significantly.

The numbers in parentheses refer to the page numbers of the strategies that specific items of information were drawn from, but these should be read in the context of each strategy as a whole.

Our comparative analysis of the discourse of policy authors and the ways that they represent policy issues shows that the transition towards a CE is not a consistent or central feature of current UK government policy. Tensions exist between the meanings ascribed to CE-relevant policy artefacts by different interpretive communities within the government. Other than the RWS, a CE does not appear to be a clear aim towards which the strategies are oriented. Where explicitly mentioned, it appears as a semantic badge rather than a meaning which permeates into the substance of the strategies. (For example, there is no reference to the circular economy in the pre-consultation Industrial Strategy green paper, whereas in the post-consultation white paper, the concept is presented in some detail in the two “inserts” without appearing to have a presence or impact in the rest of the strategy). This could be attributed to the relative novelty of CE as a driver for UK government policy (although ministerial speeches advocating a CE transition date back to 2011 [49]). Direct references to CE as a policy artefact in five out of the six strategies does, however, indicate a desire to bring the concept into the policymaking process. Figure 2 illustrates the extent to which each strategy engages with CE-relevant and nutrient-relevant policy artefacts.

Below, we explore in more detail some key issues for the development of a CNE arising from these overall findings, both in its own right and as a fundamental component of a CE more generally. We first discuss the multivalent meanings attributed to “clean growth” as the key artefact operating at the intersection of economic and environmental policy. We then specifically consider the treatment of nutrients in a CE within these strategies before highlighting the function of indicators as key devices for driving the interpretation of ambiguous policy artefacts. We go on to discuss the need for consistency of framing of policy artefacts across strategies within an overarching sustainability framework and the role of particular sociotechnical imaginaries in framing the treatment of CNE-relevant ideas. We conclude by offering some recommendations as to how future policy iterations of could better contribute to the development of a CNE. Each of the following sections contributes to one specific recommendation, other than Section 4.1, from which two recommendations are derived.

3.2. Framing of Strategies: Meanings of Clean Growth

Our analysis revealed that the policy artefact “clean growth” plays a prominent role throughout the strategies. All of the strategies assert that they are aligned with the CGS and that they contribute towards delivering clean growth. “Clean growth” thus appears to perform the role of an organising concept which aligns government thinking across departments and strategies. Its uniting of economic and environmental agendas puts it into direct dialogue with policy around CEs and CNEs, and it forms the overarching aim towards which policy related to a CE or CNE is directed. Interpretation and communication of this central concept is therefore crucial for understanding how policy actors are likely to engage with CNE-relevant policies.

Our comparative analysis indicates that “clean growth” was not a clearly defined concept, but rather it was framed in multivalent ways in the different strategies. The different interpretive communities of policy authors imbued this policy artefact with different meanings. The CGS states that “Clean growth means growing our national income while cutting greenhouse gas emissions” [42] (p. 5), a very specific and narrowly defined meaning. The RWS interprets clean growth in a considerably broader sense. It states that clean growth “includes taking action towards increasing the resource productivity of the UK and moving towards a more circular, low carbon economy” [46] (p. 130). It also interprets the purpose of the CGS as being to “set out our commitment to comprehensive action on climate change, resource efficiency and the environment” [46] (p. 130), a considerably broader meaning than the CGS’s own definition of its purpose, which is to provide a framework to grow the economy while reducing greenhouse gas emissions.

The Clean Air Strategy also explicitly ascribes a more expansive meaning to clean growth, stating that “Clean growth means growing our national income whilst tackling air pollution, protecting the natural environment, and cutting greenhouse gas emissions” [47] (p. 39). “Clean growth” is not explicitly defined in the 25-Year Environment Plan or Bioeconomy Strategy, but its deployment in those documents appears to imply a more expansive meaning (e.g., [44] (pp. 4, 9, 18) and [45] (pp. 35, 45)). The Industrial Strategy [43], meanwhile, attributes a narrower meaning to “clean growth” than that provided in the CGS, limiting it to deriving an economic advantage from low-carbon economic activity without necessarily associating this with an absolute reduction in emissions (e.g., p. 42).

This clarification of the multivalent meanings of “clean growth” indicates a tension between the interpretive communities that produced the strategies. While the repetition of “clean growth” as a policy artefact implies a degree of alignment, these different interpretations reveal the differences in meaning and intentions for policies. Different interpretations within the policy-making community can only lead to even more divergent policy interpretation by other actors that are more remote from policymaking. The expanded interpretations of “clean growth” may represent evolutions of policy, deepening and widening the scope of “clean growth” as understood across government. Alternatively, they may indicate an emerging policy gap, with various strategies aiming to deliver “clean growth” but ascribing different meanings to that objective. This has the potential for obscuring tensions and conflicts, as different interpretations of the meaning of this policy artefact are likely to drive inconsistent or even incompatible outcomes [50]. Consistent, coherent, and credible policy mixes are therefore needed to drive transformational change [32], and their absence poses significant risks to the successful implementation of policies.

3.3. Nutrients in a Circular Economy

If the transition to a CE has yet to occupy a central position within UK government policy, a CNE is an even more peripheral concept. Our results revealed proposals for policy areas that could incorporate the recovery or recycling of nutrients in each of the strategies. However, these tend to be ambivalent rather than strongly directive. The meanings of the text could be interpreted in ways that either promote or exclude movement towards a CNE. The ambiguity of a policy’s wording and framing at this level leaves the authors’ intentions unclear, with the likely consequence of even wider discrepancies between interpretations emerging at implementation.

Statements such as “We will design a new system to support the future of farming and the countryside, with a strong focus on delivering better environmental outcomes” [42] (p. 104) or “Properly implemented precision farming, resource efficiency, and better livestock and crop management can achieve more effective sustainable productivity growth” [44] (p. 36) could imply meanings which encompass the comprehensive reuse of nutrients, but they are equally open to interpretations which do not. Taking the strategies as a whole, there appears to be little focus at the UK national level on the value, which has been recognised elsewhere, of “Recycled nutrients as a distinct and important category of secondary raw materials” [25] (p. 11).

The key issue for these strategies in terms of developing a CNE is the absence of specific reference to this as a policy issue, accompanied by ambivalence around the policy artefacts and statements that could potentially incorporate a CNE within their meanings. Outside of the RWS, there is a conspicuous lack of priority for recycling nutrients back to the land. Recovering nutrients from waste is mentioned in the CGS as a possibility for future research, but current incentives around the valorisation of organic waste focus primarily on energy generation rather than on reuse as a nutrient source [51]. Where the other strategies engage with using biowastes as resources, their focus tends to be on developing higher-value industrial products such as fuels, chemicals, and pharmaceuticals, leaving the return of nutrients to the soil conceptually marginalised (e.g., [42] (p. 84) and [45] (p. 35)). These more highly specified uses for organic wastes will compete with agriculture for those wastes, which is likely to have the effect of diverting nutrients and organic matter essential for regenerating and rebuilding soils away from agricultural use and into the production of energy, fuels, and chemicals. CNE-relevant policy artefacts (e.g., biowastes as resources) appear to embody meanings that do not lend themselves to the development of a CNE and may indeed serve to undermine such a transition by diverting biowastes to other uses.

The RWS does, however, offer the potential beginnings of a vision for a CNE. Building on work dating back to the 1990s, it commits to eliminating food waste to landfills by 2030 and exploring policies to work towards eliminating all biodegradable waste to landfills by the same date. It strongly advocates AD for treating food waste that cannot be handled higher up the waste hierarchy to provide both energy and a source of nutrients. However, while it notes in passing that AD can be used to treat a range of other wastes, it focuses almost exclusively on post-farm gate food waste and garden waste, and it does not consider routes to reusing nutrients beyond AD and composting. It does, however, commit to working across the government to find synergies between food waste, other biowastes, and renewable energy, which suggests future potential for more joined-up thinking around a CNE.

3.4. Indicators of Transition to a Circular Economy

Some of the central devices for stabilising the multivalent meanings of policy artefacts are the indicators and monitoring frameworks used to measure the progress of policy strategies [33]. Indicators are powerful drivers of interpretation and shapers of implementation which promote the enactment of specific meanings from the multiple possibilities inherent in the wording of a policy. Rendering issues visible through indicators involves critical choices about what to measure and how [52]. Indicators represent the versions of meaning, which will be measured and on which success or compliance will be judged [53]. Therefore, analysis of such indicators can assist in the task of clarifying and comparing the meanings of CE-relevant policy artefacts, identifying tensions between meanings, and exploring their implications for the implementation of a policy.

While, as shown above, the transition to a CE (and particularly a CNE) is at best a peripheral concern for overall UK government policy, policy artefacts which are related to it (e.g., resource productivity and efficiency, waste reduction, reuse, and recycling) are more widely deployed across the strategies. The presence of these artefacts, albeit unevenly distributed and with varying degrees of integration, indicates the potential for strategic alignment with the transition to a CE.

It appears particularly promising for the development of a CE that artefacts such as resource productivity and recycling inform the indicators of progress in the RWS [46] (pp. 140–142). The choice of indicators for this strategy represents an explicit attempt to “fundamentally shift the focus of monitoring away from waste and towards resources, including a refocusing on measuring waste higher up the waste hierarchy [to] help Government understand how to better support the shift towards a more circular economy” [43] (p. 136). However, the UK is already performing reasonably well against many of the RWS indicators that are intended to measure progress towards a CE [54]. From 2000 to 2015, the total amount of material extraction and consumption in the UK reduced significantly, while the GDP continued to grow (therefore demonstrating increased resource productivity). From 2010 to 2014, household, commercial, and industrial waste total volumes declined slightly, total recycling rates increased substantially, and landfilling decreased modestly.

These indicators seem to suggest that the UK is already making good progress towards developing a CE. However, the stated rationale for producing the RWS was that “our use of resources is unsustainable. We use too much and are too ready to throw things away, and this waste causes damage if it is not managed properly. We can no longer ignore this” [46] (p. 15). If current patterns of waste production and management and resource use are so unsustainable, and yet the UK is performing well against at least some indicators intended to measure these patterns, then the use of these artefacts as indicators does not seem to contribute to developing a CE.

The meanings that artefacts such as resource productivity and recycling carry when used as indicators can be compared with their meanings in other policy documents. For example, the European Commission states that resource efficiency “means using the Earth’s limited resources in a sustainable manner while minimising impacts on the environment. It allows us to create more with less and to deliver greater value with less input” [55] (The UK government does not define resource efficiency). In the RWS, rates of material consumption are used as an indicator, with metrics for the gross value added per tonne (which is hoped to increase) and tonnes of materials used per capita (which is hoped to decrease). These are partial measurements of resource efficiency and productivity. However, efficiency gains per se will not reduce the total inputs required or environmental impacts generated. In a fast-growing economy, total material consumption will continue to increase because the scale of production to meet higher demand will increase faster than the efficiency of material use [56,57]. There is therefore a substantial gap between the meanings of the policy artefact “resource efficiency” as a rhetorical device (“using the Earth’s limited resources in a sustainable manner while minimising impacts on the environment”) and its meaning as embodied in an indicator of implementation (using less resources per unit of economic output).

Similarly, indicator E4 in the monitoring framework for the 25-Year Plan for the Environment [58] indicates the efficiency of agricultural production measured by the “Total Factor Productivity”. This is based on the ratio of inputs (fertiliser, labour, etc.) to outputs (meat, wheat, etc.) such that the higher the value, the more efficiently the inputs are converted into outputs. However, this excludes consideration of key factors such as the source (e.g., primary or secondary nutrient sources) and total quantities of inputs. Again, an indicator that appears to show positive effects (i.e., more efficient use of total inputs) could mask actual impacts of increasing environmental degradation.

Strategies and indicators that emphasise resource efficiency or productivity outside of a framework that seeks to decrease the total resource consumption, waste generation, and environmental impacts may thus lead to increased pressure on natural resources rather than the opposite [59]. DEFRA acknowledged the need to develop new indicators for CE [46] (p. 138), and there is considerable research available to assist the development of an enhanced indicator set, which could frame these policy artefacts differently and generate different interpretations and implementations (e.g., [60,61,62]). Given the centrality of a CNE to a CE but its relatively underdeveloped position in UK policy, this should explicitly include measures of the total nutrient flows, recovery, and recycling.

4. Discussion

4.1. A Systemic Approach to Sustainability

If “clean growth” represents the government’s ambition for these strategies, there needs to be conceptual clarity about its meaning across the suite of strategies, including whether it necessarily incorporates the transition to a CE and a CNE.

There are multiple references in each strategy about the need to complement or help deliver each other. The presence of clean growth and CE-relevant policy artefacts such as resource productivity, reuse, and recycling throughout the strategies indicates an attempt at alignment around this issue. However, it is not clear how such alignment might be realised in practice, and without a coordinating mechanism, such alignment is unlikely to be achieved. The 2021 Public Accounts Committee report on achieving the government’s long-term environmental goals found a lack of joined-up strategic collaboration between departments [63].

The policy and regulatory regimes for agriculture, products, water management, waste, and other policy areas have evolved in isolation and to address different goals [64]. However, in order to realise a transition to a CE and CNE, these will need to be realigned to promote a common, consistent framework with consistently attributed meanings. The benefits attributed to a CE do not just arise from better management of waste and resources; they reflect a systemic approach to economic and other activity [65]. While there is a need for a degree of interpretive flexibility in visions for a more sustainable future to secure widespread buy-in, excessive ambiguity can lead to those visions losing direction and credibility [66]. Without this broader systemic approach, conflicting meanings are likely to result in the creation of new market distortions, incompatible actions, unintended consequences, and further system “lock-ins” [32].

This is particularly the case for a policy area such as a CE, in which multiple interpretations abound. At least 114 different definitions of CE are in use globally, varying across dimensions relating to its aims, core principles, enablers, and impacts [24]. CE has been associated both with radical critiques of our current economic system and with an extension of neoliberal marketisation that varies little from mainstream discourse [37,59]. Under some interpretations, it appears to legitimise limitless growth and marginalise key aspects of sustainability [67]. Nevertheless, there is considerable support for the potential that ideas of circularity have for developing more sustainable economies and societies [68]. However, precisely because these ideas are capable of such widely differing interpretations, clarity and consistency of interpretation across a range of policy areas are central to their success, or else the policy will be insufficient to overcome the multiple interconnected barriers that lock us in to our current economic model [33,69].

Velenturf et al. [62] advocated for the adoption of a whole systems approach to CE policymaking in the UK. Given that aspects of CNE-relevant policy lie across multiple government departments (DEFRA and BEIS in the case of these strategies), added to which we have identified here multiple interpretive communities within departments, we strongly support this proposal. This would feature an overarching government body which brings together all the departments that need to be engaged to realise the potential of a CE. Velenturf et al. highlighted that academics, practitioners, and policy makers should work together to better understand how specific policy decisions interact with and impact a CE and wider economic, environmental, and social ambitions in the pursuit of sustainability.

While clean growth and CEs are promoted as contributing to sustainability and are often rhetorically treated as its equivalent, they do not necessarily correspond to it [70,71]. Our analysis suggests that the multivalent framings of these artefacts will lead to confusions which critically intersect with the implementation of a CE. It cannot be assumed that a CE will deliver sustainability or that clean growth will require a CE without a better understanding of how artefacts are being interpreted, the overarching aims of the public policy within which they are framed, and the contributions they are intended to make to those aims [37].

The conflicting meanings attributed to clean growth and CEs may produce unintended and even perverse consequences [64]. An emphasis on carbon emission reductions (a narrow interpretation of clean growth) leads to a focus on energy rather than resource use more widely, which a wider interpretation of clean growth that includes CEs would imply [72]. There are many aspects of environmental sustainability that neither clean growth nor CEs directly address (e.g., biodiversity loss), and neither address the social dimensions of sustainability per se [62]. A CE could end up supporting the very energy- and material-intensive modes of production and consumption that it is ostensibly intended to deliver us from through a need to continue producing ever intensifying streams of waste to feed production processes that will use it as a resource [68,73].

Therefore, as well as clearly defining how CEs and clean growth are interpreted and aligning these interpretations across strategies, there is a need to embed CE and clean growth measures and indicators in an overarching sustainability policy framework. Brandão et al. suggested that the focus of such a framework “should be on using resources wisely in a way that maximises human well-being within environmental limits” [64] (p. 506).

For a CNE, we suggest that this would mean acknowledging and rectifying the current absence of a CNE as a policy issue across the suite of UK policy and recognising the centrality of returning nutrients to land as a key aspect of the regenerative nature of a CE. This would require explicit recognition of the tensions between the interpretation of biowastes as feedstock for high-value industrial products and for building and restoring natural capital. An integrated vision for a CNE would need to be clearly articulated as part of an overarching CE policy objective to avoid the risk of being undermined by other policies which neglect the critical importance of returning nutrients to agriculture sustainably [22,74]. Explicitly and consistently connecting this objective to the priorities of all relevant strategies would provide a framing within which currently ambiguous statements of relevance to a CNE could be interpreted.

4.2. Circular Nutrient Economies and Sociotechnical Imaginaries

As well as promoting particular ideas about circularity and related concepts such as clean growth, the strategies analysed here are also embedded in particular sociotechnical imaginaries which provide the overarching context in which the meanings of policy artefacts are interpreted. Sociotechnical imaginaries are “collectively held, institutionally stabilised, and publicly performed visions of desirable futures” [75] (p. 4). They provide a lens through which we see and which we use to interpret the world. They shape the meanings and interpretations of policy artefacts in subtle yet powerful ways through taken-for-granted norms, conventions, metaphors, imagery, and meta-narratives. This in turn shapes and informs trajectories of research, innovation, policy, and practice, which in turn reinforce the imaginaries which drive them [76]. Thus, they simultaneously both enable common practices by providing a common interpretive framework and are legitimised and reproduced through those practices [77].

In these strategies, nutrients, fertilisers, and farming often appear to occupy a lower priority position than other sectors (e.g., energy, manufacturing, and chemical) and resource streams (e.g., plastics and biofuels). Where agriculture is addressed, it is generally (although to a lesser extent in the 25-Year Environment Plan) portrayed in the text and accompanying imagery as industrialised, engineered, sanitised, and thoroughly technologised with a high degree of control over its processes and components. It is presented as being more akin to a factory than an intervention in complex, open, and only partially controllable physical, chemical, biological, and ecological systems. This is indicative of a particular sociotechnical imaginary of agriculture as an industrial sector analogous to manufacturing. This in turn sits within a wider imaginary that permeates these strategies of industrial and social progress as technology-driven innovation, described by Völker et al. as “a techno-optimist model [which] rehearses an understanding of innovation and problem solving in which a seemingly inevitable technological progress provides solutions for societal challenges” [35] (p. 109).

While precision methods and advanced technologies are significant aspects of real-life farming, there is also the uncontrollable and “natural” part of the nature-culture assemblage that agriculture inevitably is [78]. The “biological route” return of nutrients from organic wastes (manures, slurries, wastewater, slaughterhouse waste, food waste, etc.) to land, with their difficult bulkiness, resistance to precise measurement and control, and cultural repulsion associated with their very nature as organic waste, does not sit easily within a technologised imaginary of agriculture, where technologically mediated precision is viewed as the solution to resource efficiency [21]. However, as Asdal and Marres warn, “It would be a mistake to assume that the ‘externality’ of nature can be suspended” [79] (p. 2057). Transitioning to a CNE will require embracing and engaging with the messiness and living materiality of agricultural systems in a way that these strategies do not alongside developing technological solutions for processing secondary nutrient sources to facilitate their transport between nutrient “hotspots” (e.g., urban and livestock production centres) and “coldspots” (e.g., centres of arable production) [10].

Therefore, even strategies that at first appear at least amenable to the development of a CNE embed the conceptual absence of the return of nutrients to land, because this does not fit easily into the imaginary of industrial agriculture performed by these strategies. The presence of this imaginary accentuates the existing vulnerability of a transition to a CNE to the unintended consequences of a narrow focus on market failures or technological barriers and a lack of engagement with wider systemic issues [32,80]. The current policy framing for organic wastes focuses on driving markets for using wastes to produce energy, chemicals, and biofuels through innovative high-tech, high-control, hyper-modern procedures. This obscures the fundamental need to return nutrients and organic matter back to soils as an integral element of a regenerative circular economy [81,82].

This current framing fits well within the sociotechnical imaginary of innovation and progress as technologically driven, scientifically precise, and inherently profitable. However, it impedes the interpretation of policy artefacts in a way that would open the possibility for the kind of broader, systems-based approach which would be required to underpin a sustainability-driven transition to a CNE and which would need to seek economic, cultural, regulatory, technical, and political levers to drive lower-tech solutions alongside high-tech ones across the food system from producers to consumers [83]. This implies a need to engage different framings and imaginaries across the suite of policy documents to enable a different set of meanings and emphases attaching to CNE-relevant policy artefacts.

5. Conclusions

In this paper, we analysed the presentation of CNE-relevant policy artefacts in six UK government strategies, finding weak to moderate engagement with such artefacts in five of the six strategies and strong engagement in the sixth. We clarified and compared the meanings attributed to these policy artefacts within and between different interpretive communities within government, identified meanings that are in tension or conflict, and explored the implications of these tensions for the implementation of policies. Across the suite of strategies, only the RWS engaged strongly with CNE-relevant policy artefacts, mobilising CE as an organising concept and emphasising the importance of returning nutrients and organic matter to the soil. We found tensions within as well as between strategies relating to CE (e.g., the Industrial Strategy made clear statements in support of CEs (including CNEs) but without this thinking permeating those statements beyond). There were inconsistencies between rhetorical and intuitive interpretations of CEs and their interpretations as indicators. While clean growth featured strongly across the strategies as a nexus point between economic and environmental policy, conflicting interpretations are likely to lead to conflicts in implementation, including with regard to the relationship between clean growth and a CE.

Our analysis suggests that current UK government policy could be amenable to the development of a CE—and within that a CNE—as an element of clean growth. However, there is a lack of clear and consistent meanings for either clean growth or a CE within and between policy texts, and a CNE is conceptually marginalised across the majority of the strategies. This produces a likelihood of incompatible interpretations and subsequent divergent actions which may undermine key sustainability benefits that are attributed to CEs and clean growth. The limited penetration of the CE concept is not sufficient to trigger the radical changes needed to drive a transition away from the locked-in linear economy. Across the strategies as a whole, the deployment of CNE-relevant policy artefacts in the context of a highly technologised, industrially oriented, growth-focused sociotechnical imaginary underplays and detracted from the importance of minimizing nutrient inputs and returning residual nutrients to the soil as a central element of a regenerative circular nutrient economy.

In order to drive a transition to circularity, government policy would require reorientation and reframing, explicitly integrating departments and strategies, and adopting a systemic approach rather than being primarily confined to one strategy. To achieve the sustainability benefits often attributed to CEs and to clean growth, they must also be set in a policy context where their contributions to the overall sustainability goals are explicit and demonstrable. In particular, considerably more attention is required for the specific development of a CNE, both as an important policy aim in its own right and as a fundamental element of a CE more generally.

Our analysis suggests a set of first steps towards achieving such a reorientation in policy. Each of the following recommendations derives from a section of our results and discussion. The section is noted in parentheses at the end of the recommendation:

• Development of an agreed definition of clean growth, consistently shared across government departments, policy documents, and audiences, encompassing the broader elements that would secure the sustainability objectives often associated with but effectively excluded by a narrower definition (Section 3.2);
• Development of an agreed understanding of a regenerative CNE, consistently shared across government departments, policy documents, and audiences, incorporating explicit emphasis on the return of nutrients and organic matter to the soil, soil health, and soil fertility (Section 3.3);
• Development of a new set of indicators for CEs and CNEs capable of measuring progress in terms of agreed meanings of key policy artefacts in the context of the overarching sustainability framing (Section 3.4);
• Explicit assessment of future economic and environmental policies, programmes, and projects in terms of whether, how, and to what extent they contribute to or align with this shared understanding of a regenerative circular nutrient economy (Section 4.1);
• Establishment of a cross-departmental body with the responsibility of coordinating departmental strategies under an overarching sustainability objective (provisionally, “using resources wisely in a way that maximises human well-being within environmental limits” [64] (p. 506)) to ensure the alignment of policy artefact meanings (Section 4.1);
• Reflexively attending to the sociotechnical imaginaries performed by strategy documents, with a view toward realigning them with alternatives (e.g., of thriving, inclusive, and sustainable communities of sufficiency embedded in and entangled with the natural world) (Section 4.2).

This intervention is particularly timely, as it has the opportunity to inform the development of policies and strategies that will shape the UK’s medium-to-long-term economic recovery from the COVID-19 crisis and post-Brexit industrial, agricultural, and environmental policy. The UK is at a crucial juncture in which government action will determine whether it remains locked into a linear economic system for decades to come or accelerates the transition to a more sustainable and more circular economy. More broadly, this analysis serves as a case study with the wider application of an advanced industrial nation attempting to develop more sustainable economic and environmental policies but hampered by the development of policies (1) in silos across which policy artefacts are imbued with different and potentially contradictory meanings, (2) within a sociotechnical imaginary which tends to obscure and marginalise a vital element of the circular economy, and (3) without an agreed understanding of the overarching sustainability aims of public policy.