Guidance

Make off-site biodiversity gains as a developer

How developers can create and enhance habitat off-site or buy biodiversity units to achieve biodiversity net gain (BNG).

Applies to England

Biodiversity net gain (BNG) is mandatory from 12 February 2024.

You can view all of the BNG guidance in the BNG collection.

Why developers may need to make off-site gains 

Under biodiversity net gain (BNG) legislation, developers must deliver 10% BNG, as measured by the statutory biodiversity metric.  

The guidance on this page assumes a development is subject to BNG

The 10% uplift is required whether or not the development impacts existing biodiversity. 

You cannot create off-site biodiversity gains by removing habitats and then putting them back. If you damage habitats on your land, you’ll have to make up for the damage before you can make a gain.

Once created, off-site BNG gains must be maintained for at least 30 years. 

There are 3 ways a developer can achieve 10% BNG

  1. Enhance and restore biodiversity on-site (within the red line boundary of a development site). 

  2. If developers cannot achieve all 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. This should be a last resort. The government will use the revenue to invest in habitat creation in England.  

You can combine all 3 steps, but must follow the steps in order. This order of steps is called the biodiversity gain hierarchy

This guidance is about ‘how to make off-site gains’ if you cannot achieve your BNG on-site, which is step 2. 

What counts as off-site 

Off-site means outside the red line boundary of a developer’s site. This includes any habitat within the blue line boundary. 

Other work you can count as part of your off-site BNG   

If you’re already enhancing or funding off-site habitat enhancement (that’s in relation to your development), you may be able to count this towards your BNG. The same rules on what you can count apply across both on-site and off-site BNG.   

Some schemes only count in part towards your BNG. There is more information available on what you can count towards a development’s BNG

Selling off-site units on existing developments 

As a developer, if you own developments which were granted planning permission before BNG came into effect, you may wish to consider selling off-site units on the habitat. To do this, you should follow the guidance for land managers wanting to sell off-site units. You will need to take into account any existing management plans or restrictions on the habitat. 

Choosing where to achieve off-site biodiversity gains  

Biodiversity gains may be delivered anywhere in England, but you should consider the following when deciding where to source your off-site biodiversity gains. 

The biodiversity metric incentivises off-site gains close to your development. This is so that communities local to the development benefit from increases in biodiversity. Except for intertidal, watercourse or linear habitat, off-site gains in a neighbouring local planning authority (LPA) will be worth fewer biodiversity units than off-site gains in the same LPA as the development. Off-site gains beyond the neighbouring LPA will be worth even fewer. 

The metric also provides an incentive to achieve off-site biodiversity gains in areas of strategic significance. Strategically significant areas are set in your local nature recovery strategy. Where this is not yet available, your LPA may recommend you use a draft strategy, or an alternative strategy. You can find your LPA

Make off-site gains  

You can either buy off-site units from a land manager, or make off-site gains on your own land outside the development site. If you make off-site gains on your own land, you are the land manager as well as the developer, so you will need to follow both steps: 

Steps to follow 

This is an example order of steps, but the order of some steps is flexible.   

You can buy off-site biodiversity units before, after, or at the same time as the land manager registers the gain site. You can also buy off-site biodiversity units before, after, or at the same time as the units are allocated to your development. 

The 30-year BNG commitment starts from the completion of habitat enhancement works, as defined in your legal agreement. 

Habitat creation, enhancement and management on a gain site can begin before its allocation to you. You can also allocate units to your development before the habitat work starts.

1. Use the biodiversity metric  

First do a survey of habitat before development and explore on-site options to achieve your BNG using the biodiversity metric. If you can only partially meet your BNG on-site, or cannot meet BNG on-site at all, you should explore off-site options. For example, recalculate using the statutory biodiversity metric tool to see how to achieve all your BNG using a combination of on-site and off-site, or entirely off-site.  

If you cannot achieve all your BNG either on-site or off-site or through a combination of these, you will have to meet any BNG you are missing by buying statutory biodiversity credits

2. Find off-site units for sale 

If you choose to buy off-site units, you will need to explore the marketplace to find what is available to buy.

You can consider searching for a gain site that: 

  • will create and enhance habitat to meet the needs of your specific BNG requirements 
  • has already started creating and enhancing habitat that meets your BNG needs  

You can buy off-site biodiversity units: 

  • directly from a landowner 
  • from a habitat bank operator  
  • through a broker 
  • from a trading platform 
  • from your LPA (if they provide this service) 

The land manager you buy from will need to register the gain site on the national biodiversity gain sites register before, at the same time as, or after you buy units on it.   The purpose of the register is to show how and where developments are improving biodiversity off-site. It also prevents ‘double counting’, which would happen if the same units were assigned to multiple developments. Sites on the register may be allocated to specific development projects to help them achieve their biodiversity gain target. The register does not contain contact details of available gain sites and is not a ‘matchmaking’ service to connect buyers and sellers.  

Buyers and sellers will find each other through the private market. To explore the private market, you could: 

  • search online  
  • consult a land agent, broker or another consultant 
  • speak with land managers you already have links with  
  • speak with your LPA, who may be able to signpost you to sellers in the market and in some cases may act as informal brokers 
  • speak with habitat bank operators who would organise a sale for you 

A legal agreement secures a gain site for BNG and sets out who will do the BNG creation, enhancement and management work for 30 years.  

You can choose off-site habitats which are already legally secured and registered. If you do this, those off-site habitats do not need to be legally secured again. If you want to use off-site habitats which do not already have a legal agreement, you must enter a section 106 agreement before you get planning permission. 

Find out how to enter a legal agreement for biodiversity net gain.

4. Get planning permission  

You do not have to buy off-site units before applying for planning permission but you can if you wish. You cannot start your development before the approval of your biodiversity gain plan, later in the process (step 7). 

There is information on what developers need to provide to LPAs with the planning application.

5. Agree to buy units 

It is up to you how you arrange the sale, including any contract of sale you may choose to have with the land manager. You may want to seek legal advice on the sale. 

When planning a contract of sale, you should consider including: 

  • the number and type of units to be registered and allocated to your development 
  • a commitment from the land manager to apply to record the allocation of units once you have paid 

Prices and payment terms should be agreed between you and the seller.  

You may be able to pay a landowner an initial deposit, with payment in full when units are allocated to your development.   

You’ll need to agree whether you’ll pay by: 

  • lump sum 
  • staged payment 
  • results 

6. Record the allocation of off-site gains to your development 

Once you have found a provider of biodiversity gains and agreed a contract with them, either the land manager or you (with the land manager’s permission) must apply to record the allocation of the biodiversity units to your development on the biodiversity gain sites register.

If the biodiversity gain site you have chosen is not yet registered, you can either: 

  • wait for the provider to register the site and then apply to record the allocation of gains to your development 
  • apply to record the allocation of gains to your development at the same time as applying to register the site 

The allocation of any off-site biodiversity gains to your development will need to be recorded before the LPA can approve your biodiversity gain plan.  

7. Submit a biodiversity gain plan  

If you can meet your BNG requirement with off-site gains, and have recorded the allocation of any off-site biodiversity gains you’re using, you’re ready to complete your biodiversity gain plan and submit it to the LPA.

The LPA will check that any off-site gains in your biodiversity gain plan are registered and allocated. You should provide the unique biodiversity gain site number (which the site was given when it was registered by the land manager) in your gain plan.  

The LPA has 8 weeks to approve or refuse your biodiversity gain plan.

8. Deliver 10% BNG for at least 30 years 

Off-site units must be maintained to deliver 10% BNG for at least 30 years after the completion of habitat enhancement works, as defined in the legal agreement. 

If the habitat creation, enhancement and management work has not yet started by the time you buy off-site units, it should start within 12 months of allocation. 

The land owner is legally responsible for creating or enhancing habitat, managing that habitat for 30 years and delivering the agreed BNG.   

If you make off-site gains on a site you own, you’re the land owner. If you buy off-site units, you’re paying the land owner to manage the land for 30 years and deliver your required BNG

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Published 29 November 2023
Last updated 28 February 2024 + show all updates
  1. Added a link to information on what developers need to provide to LPAs with the planning application.

  2. Updated box at top of page to state that biodiversity net gain (BNG) is mandatory from 12 February 2024 and removed the 'draft guidance' label. Other changes throughout, including legal agreements, biodiversity gain plan and adding links to the register.

  3. First published.