After a long process of scrutiny, debate and amendment, the Environment Act 2021 (“the Act”) finally received royal assent on the 9th November last year. It sets out a statutory framework for post-Brexit environmental protection and regulation, to be overseen by the newly created Office for Environmental Protection.[1] Some of the provisions of the Act simply carry over existing protections from EU legislation, but others are genuinely new. One of the new provisions concerns mandatory Biodiversity Net Gain (BNG) requirements to be introduced as a condition of planning permission. The principle behind these requirements is that new developments should leave the natural environment in a measurably better state than they found it in order to be acceptable in planning terms.
The relevant provisions in the Act itself are to be found at Part 6: sections 98–101 and Schedule 14 and are summarised below.
- The Town and Country Planning Act 1990 has been amended to introduce a mandatory minimum 10% gain in biodiversity.
- The requirement that this gain be calculated according to Natural England’s Biodiversity Metric 3.0 and that the proposed steps to be taken to achieve it are set out in a developer’s ‘Biodiversity Gain Plan’.
- BNG will be deliverable on-site, off-site, or via the purchase of ‘biodiversity credits’ from central government.
- Habitats delivered via the policy are to be secured for at least thirty years via planning obligations or conservation covenants.
- Biodiversity gain sites will be registered on a newly established national public register.
The policy is due to come into force in November 2023 but, notwithstanding the provisions of the Environment Act, many details of its operation are yet to be fleshed out via secondary legislation. Defra is currently consulting on how BNG will work in practice.[2] The subject is a complex and technical one and I do not profess to be any kind of expert, but in the remainder of this piece I hope to provide an overview of the scope and some of the key features of what is being proposed, as well as considering a few potential barriers to the successful implementation of the policy and the adequacy or otherwise of the government’s proposed solutions.
What kinds of development are covered by the new proposals?
Under current proposals, the new BNG requirements will apply to a wider range of developments than initially anticipated when the Environment Bill was first tabled. For example, a government amendment introduced in June of last year expanded the requirement to include Nationally Significant Infrastructure Projects (NSIPs). Defra’s consultation document notes that there may be circumstances where a particular NSIP is unable to deliver the 10% minimum BNG required from schemes delivered through the normal planning process but prefers a reduced percentage target in such circumstances to a blanket exception for large scale projects [p. 41]. One can only imagine the number of planning inquiries which are likely to arise after the introduction of the policy, dealing with the question of whether a particular percentage target is appropriate in a given set of circumstances Crucially, however, 10% will remain the baseline target, even for NSIPs.
The government is also now proposing to apply the 10% target to schemes on brownfield sites, despite previously considering exempting such developments from BNG requirements. The rationale behind the change is that brownfield exemptions would “deliver little added benefit and would greatly complicate the requirement’s scope for developers and planning authorities alike” as well as a stated desire for the policy to benefit people as well as wildlife, by improving the biodiversity of sites in urban and suburban areas, where brownfield land tends to be concentrated [p. 26]. Previously considered exemptions for temporary planning permissions and schemes in conservation areas and national parks have also been abandoned.[3]
Some exceptions remain in the consultation proposals, including householder planning applications such as extensions and permitted development, the former presumably in the interests of avoiding unfairness to individual householders for the sake of minimal benefits, and the latter because permitted development rights operate outside of the usual planning process and do not normally involve substantial additional land take or construction work. Defra is also considering exemptions for self-build, custom build, and the creation of biodiversity gain sites themselves (the role of these sites is discussed more fully below) [pp. 23–27]. Nevertheless, the consultation document seems to indicate a commitment to apply the policy more widely than many in the environmental and development sectors had previously anticipated.
How will the policy work?
The consultation document makes clear that the new statutory BNG requirement is designed to complement the existing biodiversity mitigation hierarchy set out in paragraph 180a of the National Planning Policy Framework. Developers should in all cases aim to avoid or reduce biodiversity impacts through site selection and layout. In terms of meeting their 10% BNG target, they should preferably seek to do so through on-site improvements, with the resulting habitats being secured for at least thirty years via planning obligations or conservation covenants. In the event that on-site delivery is not feasible, developers will be permitted to meet the requirement off-site, either through improvements elsewhere on their land, or by purchasing off-site benefits to be achieved via biodiversity gain sites elsewhere. As a last resort, if no other option is feasible, they may purchase biodiversity credits from central Government. The biodiversity gains and losses of a development will be measured in ‘biodiversity units’, using Natural England’s Biodiversity Metric 3.0. This metric uses habitats as a proxy for biodiversity and calculates units by taking account of their type, extent and condition. Developers will be able to purchase biodiversity units on the market when meeting their BNG target via off-site contributions.
Under the new policy, all applications for planning permission which do not fall under one of the proposed exceptions will need to provide initial BNG information, including:
- the pre-development biodiversity value,
- the proposed approach to enhancing biodiversity on-site, and
- any proposed off-site biodiversity enhancements (including the use of statutory credits) that have been planned or arranged for the development.
To fully discharge the new planning condition, local planning authorities will need to approve a development’s biodiversity gain plan. These plans should offer a more detailed road map for how the developer proposes to achieve the benefits to biodiversity indicated as part of their initial planning application. The consultation document contains a template plan at Annex B. The approval of a biodiversity gain plan must take place before development starts [p. 13].
Biodiversity gain sites will be registered on a newly established Public Biodiversity Gain Site Register, to aid enforcement and avoid double counting. In the interests of transparency, the register will be designed so that local communities are able to access information on the delivery of sites and monitor their progress over time.
Will the policy be effective?
While the introduction of the mandatory BNG policy has been broadly welcomed in the environmental sector, conservationists and biodiversity experts have raised a number of serious issues with the current proposals and questioned the efficacy of the government’s proposed solutions to them. A non-exhaustive list of these issues includes fears over the loss of irreplaceable habitats, the design of the algorithm for Natural England’s Biodiversity Metric, delays in the delivery of replacement habitats, and the challenges of enforcement.[4]
Irreplaceable habitats
As noted above, the new BNG policy is supposed to complement existing planning protections for habitats and the mitigation hierarchy enshrined in the NPPF, not replace them. Campaigners and academics alike have called on the government to take this opportunity to firm up its commitment to protecting irreplaceable habitats such as ancient woodland, blanket bog, limestone pavement, sand dunes, salt marsh and lowland fen, arguing that it should be all but impossible for developers to achieve planning permission for schemes which would result in the destruction of these vital ecosystems.
Irreplaceable habits have been removed from scope of the current BNG consultation, so as not to give the impression that losses in such habitats can be offset in the usual way. However, when a development results in losses of both irreplaceable and non-irreplaceable habitat, the BNG requirement will still apply to any affected non-irreplaceable habitat. Defra has promised supporting guidance on what constitutes irreplaceability and proposed to adopt a bespoke compensation approach where developments would lead to the loss of irreplaceable habitat. The consultation document suggests that the appropriate compensation would typically exceed standard BNG requirements [p. 31].
While the recognition that the value of irreplaceable habitats for biodiversity cannot be assessed in terms of standard units under the general Biodiversity Metric is welcome, the language of ‘compensation’ and refusal to tighten restrictions on the destruction of such habitats is deeply concerning. The value to nature of an acre of ancient woodland cannot be adequately compensated in money, no matter how many trees one pays to plant. Without stronger protections, there is a very real risk that developers of schemes which are likely to be particularly profitable, but which will also lead to irreplaceable habitat loss, will be quite content to throw money at the problem in the form of compensation.
The Biodiversity Metric
Many rewilding experts have raised serious concerns over the way that Natural England’s algorithm calculates the value of a given habitat for biodiversity. The algorithm uses information about the type, size and condition of a habitat to assign it a number, defining how valuable it supposedly is for biodiversity. However, critics have warned that the new Biodiversity Metric does not value scrubby landscapes characterised by bramble, thistle and ragwort, which are often key features of rewilding projects. Such characteristics are logged as a sign of the ‘degradation’ of a landscape. In this respect the algorithm privileges more traditional conservation projects over innovative rewilding schemes, which seems a great shame when these projects can actually provide some of the most genuine and lasting benefits for biodiversity.
Speaking to the Guardian, entomologist Steven Falk noted that quarries and field margins were among habitats undervalued by the algorithm and labelled as ‘degraded’, despite being very rich for wildlife. He highlighted the risk that assessments based on the Biodiversity Metric would therefore conclude that such habitats did not need to be compensated for at all.
The algorithm also does not take into account the location or interconnectedness of a habitat. Scrubland next to a carpark and scrubland in the middle of a large rewilding project would consequently be afforded the same purported value for biodiversity under the current metric, even though the difference in their actual value would be transparently obvious to a human observer assessing them in their physical context.
Delay and enforcement
The government’s stated aim is for net gains to be delivered quickly.The consultation document proposes that on-site gains should be secured for delivery within 12 months of the development being commenced or, at the very least, before occupation. Biodiversity gain plans will have to set out a full timetable for implementation of their proposed measures. Any delay in the creation of replacement habitats for longer than 12 months will have to be reflected in the biodiversity metric calculation, meaning that developers who delay will ultimately have to pay more [p. 54].
However, the issue of delay in the delivery of offsets is closely linked to that of enforcement. Planning departments and councils are underfunded, understaffed and overstretched already. The introduction of the new BNG policy will leave them with yet another mandatory consideration to assess at the decision-taking stage and there is a danger that local planning authorities have neither the time nor the expertise to do it properly.
When Rebecca Moberly, principal consultant for the Planning Advisory Service (PAS), was quoted in a recent piece for ENDS report, she expressed her concern that the proposals for the implementation of the policy are too vague to be properly enforceable and that developers and landowners might be able to fudge the numbers. “We still don’t know if this will be part of the planning process or something separate,” Moberly said. “Developers might say they have done it, but who is going to check it? And if it has not happened, who will make sure it does happen?” If fears about the lack of capacity in the system prove to be justified, then delays in the delivery of off-sets may prove to be the least of environmentalists’ worries.
Alongside the publication of the its consultation document, the government announced a new £4 million funding pot to help local authorities with implementation costs. This works out at a rather meagre £10,000 per local authority, which hardly seems sufficient to cover the cost of enforcing a whole new governance framework.
It is hardly surprising, therefore, that when ecological economist Sophus zu Ermgassen and a team of researchers from the University of Kent assessed 6% of the housebuilding in England between January 2020 and February 2021, in six local authorities who had adopted the BNG scheme ahead of its national rollout, they found evidence of a governance gap and that promised biodiversity units were not being delivered. Overall, they found that BNG developments led to a 34% reduction in green space, offset by promises of a 20% increase in total biodiversity through the theoretical delivery of smaller but more ecologically valuable habitats. Whether or not these promised gains will materialise remains to be seen.
The BNG policy has the potential to lead to some genuinely positive outcomes in terms of habitat creation, especially where a development takes place on denuded agricultural land (and an awful lot of land in England is exactly that). If properly enforced, it could constitute a valuable source of funding for conservation, rewilding and habitat creation projects. Or it could turn out to be unwieldy, overly financialized, and ultimately unenforceable, allowing developers to destroy thriving ecosystems and interconnected habitats and then plant a few trees elsewhere or buy a few extra credits. If the policy is to be more than greenwash, there needs to be proper government support available to local authorities to enforce it and decision makers must prioritise ecological outcomes when assessing whether a given development meets its obligations. Otherwise the risk is that all BNG will create is a low quality market in off-sets.
[1] Analysis of the range of targets included in the Act and of the objectives, functions and draft strategy of the OEP can be found in two recent posts on FTB’s Environmental Law Blog.
[2] Defra, Consultation on Biodiversity Net Gain Regulations, closes 5 April 2022. Page ranges given in square brackets refer to this document.
[3] Conservation areas for this purpose include Sites of Special Scientific Interest, Special Areas of Conservation, Special Protection Areas and Marine Conservation Zones.
[4] These issues and others are addressed in a case study of six early-adopter councils already implementing mandatory BNG policies by Sophus zu Ermgassen et al., ‘Exploring the ecological outcomes of mandatory biodiversity net gain using evidence from early-adopter jurisdictions in England‘, Conservation Letters, Vol. 14, June 2021.
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