Biodiversity Net Gain: Key Considerations for Developers and Landowners

The landscape of property development and conservation has changed with the introduction of mandatory Biodiversity Net Gain (BNG) requirements, presenting both challenges for developers and opportunities for landowners.

Biodiversity Net Gain is a legal mandate by the Environment Act 2021, aimed at improving natural habitats by ensuring that any housing, industrial or commercial development leaves nature in a better state than it was found.

Biodiversity Net Gain is a now mandatory requirement for new planning applications made under the Town and Country Planning Act 1990.

Developers must now integrate Biodiversity Net Gain principles into their planning proposals to ensure clarity and compliance, whilst landowners have a chance to create conservation projects that generate revenue by making biodiversity units available to developers.

What is Biodiversity Net Gain?

Biodiversity Net Gain is important environmental legislation aimed at enhancing biodiversity in the context of new development. It’s a policy requiring developers to leave the natural environment in a better state than before development.

Specifically, it mandates that the biodiversity lost due to construction or other activities must be compensated for by creating or restoring habitats on-site, off-site or through a combination of on-site and off-site measures. This ensures that the overall biodiversity is increased rather than diminished.

Biodiversity Net Gain involves thorough assessments of the existing biodiversity on a site and planning measures to improve it, such as:

  • Ensuring the preservation or reduction of any loss of current biodiverse habitats on a development site.
  • Enhancing or expanding the biodiverse habitats present on the development site.
  • Establishing a partnership with an off-site habitat gain provider to enhance biodiversity in other locations, resulting in a combined net gain of 10% across multiple sites.
  • Utilising government Biodiversity Net Gain credits only as a last resort, as they are priced to discourage this option whenever possible. The national Biodiversity Net Gain credits scheme allows developers to purchase statutory ‘credits’ with the revenue generated being invested by Natural England nationally in habitat creation and enhancement projects.

What are the Biodiversity Net Gain rules for developers?

In England, developers must ensure that new development projects contribute to a measurable increase of 10% in biodiversity, as mandated by the Environment Act 2021.

This rule applies to most developments starting from February 12, 2024, and all projects from April 2, 2024, with some limited exceptions.

Developers can enhance biodiversity on-site or off-site, or purchase government Biodiversity Net Gain credits, if necessary. However, they must prioritise preventing the loss of existing biodiverse habitats on-site whenever possible.

These biodiversity gains must be maintained for at least 30 years, in the case of both on-site and off-site provision. Local planning authorities may also enforce policies requiring biodiversity gains exceeding 10%.

When does Biodiversity Net Gain apply?

Biodiversity Net Gain rules apply to all new developments seeking planning permission, with specific exemptions.

Until April 2, 2024, small sites are exempt, defined as residential developments with nine units or less on a site with a maximum area of 1 hectare, or non-residential developments creating a floor area under 1000m² or less than one hectare in size.

Ongoing exemptions exist for developments which don’t impact priority habitats and disturb less than 25 square meters of habitat or less than 5 meters of linear habitats such as hedgerows.

Self-build and custom-build projects with a maximum of nine dwellings on sites no larger than 0.5 hectares, where all properties are self-build or custom-build, are also exempt.

Small housebuilder projects such as home extensions and loft conversions also have exemption options available.

Biodiversity Net Gain aims to ensure sustainable development practices across small and large development projects that impact the surrounding environment.

Biodiversity Net Gain for developers

Developers must show they will deliver at least 10% Biodiversity Net Gain before the local planning authority will grant planning permission.

If this is unachievable within the development site boundaries, developers can pay other landowners and land managers to undertake offsite habitat improvement in their place.

As a last resort, biodiversity credits can be purchased. All options add significant costs to any development caught by the Biodiversity Net Gain requirements.

Biodiversity Net Gain for farmers

Biodiversity Net Gain offers farmers new opportunities to secure additional income and new revenue streams.

Farmers have a crucial role in managing large parts of the countryside and can contribute to Biodiversity Net Gain.

However, it is advisable for farmers to consider the legal implications of new agreements and how they may affect existing agreements with developers in their farming business.

As Biodiversity Net Gain must be maintained for at least 30 years, a major consideration for farmers is whether to take land out of food production for such a long time.

There are also other practicalities to consider, including the implications for managing the land, future options for use, and the tax implications of removing it from agriculture.

Biodiversity Net Gain for landowners

Rural landowners will also have the option to work with local developers in providing offsite opportunities for Biodiversity Net Gain.

This will provide an additional long-term income stream from land which otherwise may not be particularly productive from a purely agricultural perspective.

If you are a landowner considering offering your land for off-site Biodiversity Net Gain, you must have the right planning conditions for biodiversity net gain, this includes being registered on the Natural England Biodiversity Site Register and having a site-specific habitat management plan in place.

The land identified for potential offsite provision will also need to be professionally assessed to establish that sufficient uplift in biodiversity can be generated on the land.

How can Butcher & Barlow help with Biodiversity Net Gain?

Leveraging our extensive knowledge in both the development and rural sectors, we provide practical yet strategic legal advice tailored to your objectives.

From advising landowners on the short and longer-term implications of committing land to the scheme to negotiating and agreeing on the documentation between landowners and developers, and s.106 planning agreements with the planning authority, we support you every step of the way to achieving your Biodiversity Net Gain scheme objectives.

Whether you are a landowner exploring conservation opportunities or a developer striving for compliance, we are here to advise and guide you, trust Butcher & Barlow to be your partner in achieving sustainable development goals whilst preserving our natural heritage.

Our Commercial Property Team remain available for advice and guidance on any existing or new matter.

Please get in touch via or directly with your nearest office to arrange an initial meeting.

Our Biodiversity Net Gain specialists

Our Commercial Property and Agriculture and Rural Affairs teams are made up of 18 Solicitors working from 7 of our 11 offices.

Our partner-led team has extensive experience acting for landowners selling land for development and are perfectly placed to work in collaboration with other professionals to achieve landowners’ biodiversity net gain scheme objectives.

Rachel Martin, Partner, Commercial Property

Mike Bracegirdle, Partner, Agriculture and Rural Affairs

David Burrows, Senior Solicitor, Property Development

Seema McWilliam, Partner, Commercial Property

Rebecca Jepson, Partner, Commercial and Agricultural Property

Get in touch to find out how we can help you achieve your Biodiversity Net Gain goals.