Register your interest in a legal agreement to regulate an offsite biodiversity net gain site

Biodiversity net gain (BNG) is a way of creating and improving natural habitats. BNG makes sure development has a measurably positive impact (‘net gain’) on biodiversity, compared to what was there before development. Developers must deliver a biodiversity net gain of 10%. This means a development will result in more or better quality natural habitat than there was before development.

How you can achieve BNG

There are 3 ways that a developer can achieve 10% BNG:

  1. They can enhance and restore biodiversity on-site (within the red line boundary of a development site).
  2. If developers can only achieve part of their BNG on-site, they can deliver through a mixture of on-site and off-site. Developers can either make off-site biodiversity gains on their own land outside the development site, or buy off-site biodiversity units on the market.
  3. If developers cannot achieve on-site or off-site BNG, they must buy statutory biodiversity credits from the government.

In relation to option 2 , offsite Biodiversity Gain Sites can be set up on land to increase it's biodiversity value, which would create 'biodiversity units' that can then be sold to developers. The developer can use the biodiversity units to compensate for damage caused to existing habitats on their development sites in order to achieve their 10% BNG.

New requirements have been introduced to regulate and monitor offsite Biodiversity Gain Sites.

New requirements

From January 2023 (as set out in the Environment Act 2021), habitats created for offsite biodiversity net gain must be secured for at least 30 years through a legal agreement. This can either be an S106 agreement with us or a Conservation Covenant with a Responsible Body.

Our application to become a Responsible Body for the purposes of Conservation Covenants has been approved, however at present we are only entering S106 agreements for offsite BNG sites in Buckinghamshire. If our position changes and we do start offering Conservation Covenants in the future we will update the information here.

You must enter into a legal agreement before you can add off-site biodiversity units onto Natural England's Biodiversity Gain Site register and then sell them to developers.

Our off -site biodiversity net gain Regulation Service

We offer a paid service to help with the setting up and then regulation of a legal agreement associated with an offsite BNG site.

The S106 agreement:

  • binds the landowner and any successors in title
  • means that we will ensure that the landowner (or another person) manages the habitat to the standard set out in the Habitat Management and Monitoring Plan we agree with them (for 30 years after the work is completed)

View a draft S106 agreement PDF, 302KB.

We will accept registrations of interest from:

  • landowners
  • agents
  • habitat bank brokers
  • developers

Requirements for offsite BNG sites

We will only consider regulating offsite biodiversity gain sites that deliver the best outcomes for biodiversity in Buckinghamshire.

We have produced a set of criteria that you will need to be meet before we will consider entering a legal agreement.

View the full offsite BNG site criteria PDF, 501KB.

How much it costs

If we enter a legal agreement with you, we will charge you:

  • a set-up fee to cover the time spent for us to review your proposal and draft the legal agreement (the cost will depend on the complexity of the proposal but will between £9,000 to £15,000. An estimate will be given when you register your interest)
  • a biodiversity monitoring fee to cover the cost of monitoring the progress of the habitat creation for 30 years, the cost will be based on the size of the site and technical difficulties and can be paid in instalments

Register your interest

Once you register your interest and provide supporting evidence, we will check if you meet the offsite biodiversity net gain site criteria for us to consider entering into a legal agreement with you. It's free to register your interest.

Register now

If the proposal meets our requirements

If the proposals meet our requirements, we will consider entering a legal agreement which will:

  • secure the 30 year habitat management of the site (you will need to agree to pay the Council a Biodiversity Monitoring Fee for the duration of this agreement)
  • allow you to then register the site on the National Biodiversity Gain Site Register to start selling BNG units