The Environment Act 2021, One Month On: Biodiversity Net Gain

The Blog


The eagerly anticipated Environment Act (“the Act”) received its Royal Assent on 10th November 2021 after almost three years in Parliament, resulting in the proposed changes being passed into Government law and superseding the Environment Act 1995. The Act seeks to transform previous environmental guidance by putting environmental principles into law in the hope of further protecting nature and improving biodiversity by working with developers and owners. These changes are anticipated to be incorporated into the Town and Country Planning Act (“TCPA”) in Autumn 2023.

So what are the planning implications of the Act?

There is a much sharper focus on conserving and enhancing biodiversity in the context of new development, with provision for biodiversity net gain (“BNG”) to be a condition of many planning permissions in England. More specifically, the Act requires new developments to provide a minimum of 10% increase in the biodiversity value of land being developed. The onus will be on individual Local Planning Authorities (“LPA”) to ensure 10% BNG is delivered, meaning that a suitable mechanism will need to be in place to ensure successful delivery within new developments. Given the numerous challenges currently faced by LPAs as a result of the pandemic and a chronic lack of resources, it is uncertain as to when these mechanisms will be devised, however it is likely that the strategy will be informed by emerging policies as draft development plans proceed to adoption.

The Act sets out the following key aspects to mandatory BNG:

  • Minimum 10% net gain required, calculated using a Biodiversity Metric (Natural England have provisionally launched “Biodiversity Metric 3” which will continue to be updated until 10% BNG becomes mandatory within the TCPA) and approval of a BNG plan;
  • Habitat secured for at least 30 years via obligations or conservation covenants;
  • Habitat can be delivered on site, off-site or via statutory biodiversity credits (in hierarchical order of preference); and
  • National register for net gain delivery sites (this is currently being developed by Natural England and will be publicly accessible; it will detail the baseline biodiversity value of the delivery site and the expected future biodiversity value of that site).

The mitigation hierarchy of avoidance, mitigation and compensation still applies in terms of biodiversity loss. It will apply to Nationally Significant Infrastructure Projects but not to marine development and does not change existing legal environmental and wildlife protections.

It is anticipated that the 10% BNG will become mandatory upon amendment of the TCPA towards the end of 2023; the Act states that secondary legislation will determine the precise date for 10% BNG to become mandatory. With this in mind, BNG should now be an early consideration for developers when thinking about the feasibility of a scheme and BNG plans should form part of most planning application submissions, particularly on sites of high ecological value, with a view to pushing towards the 10% BNG figure.

There is currently a lack of information regarding exemption sites and thresholds to the 10% BNG figure. However, DEFRA’s initial consultation document suggests that developments such as brownfield sites with no existing habitat potential, minor residential schemes, extensions and major infrastructure projects would not be expected to meet this specific requirement, but may perhaps be expected to incorporate other green infrastructure or demonstrate a lower percentage of BNG. This will become clearer with the issuing of secondary legislation.

One month on from the Act’s Royal Assent

It seems that a number of local authorities are already seeking to ensure new developments can demonstrate BNG and existing BNG policies are now being actively promoted by LPAs. Nexus is also aware of a number of emerging local plans which are approaching adoption that include policies requiring 10% BNG on site for new development; Ashfield District Council’s Draft Local Plan for 2020 – 2038 is one of many which specifically requests that proposals affecting biodiversity achieve a minimum net gain of 10% on site and include a biodiversity assessment.  It is therefore expected that this type of policy requirement will appear more frequently as LPAs progress with the adoption process of emerging development plans. Given the Act’s Royal Assent, it is likely that more LPAs will or are placing additional weight on both existing and emerging BNG policies and push towards the 10% figure in the run up to the updating of the TCPA.

Ultimately, the Act’s requirement for development to achieve 10% BNG is a significant but important challenge faced in the long term goal of improving the natural environment. Developers are therefore strongly encouraged to consider BNG and biodiversity assessments at the early stages of development to inform the design process. This will ensure a smoother transition as the Act’s legislation is passed into planning law and further local policies.

Authored by Hannah Hiscock, Planner