What is Biodiversity Net Gain?
Biodiversity Net Gain (BNG) is a statutory planning requirement in England that requires most new developments to deliver a measurable improvement in biodiversity.
In simple terms, development must result in habitats that are in a better condition than before, with a minimum 10% biodiversity net gain secured for the long term.
Biodiversity Net Gain is assessed at the planning stage and forms part of the planning decision, rather than being an optional or post-consent consideration.
This page is intended for developers, home owners, architects, planning consultants, ecologists, and local planning authorities who need a clear explanation of Biodiversity Net Gain.
Why Biodiversity Net Gain exists
Biodiversity Net Gain was introduced to ensure that development contributes positively to the natural environment, rather than resulting in a net loss of habitats.
The intention is not to prevent development, but to ensure that growth and environmental improvement can be delivered together through a structured and transparent system.
The BNG framework provides a consistent approach so that biodiversity outcomes can be planned, measured, and secured over the long term.
On-site and off-site Biodiversity Net Gain
Where possible, Biodiversity Net Gain should be delivered on-site through habitat creation or enhancement within the development boundary.
However, not all sites are able to achieve the required biodiversity net gain on-site due to size, layout, viability, or other planning constraints.
In these cases, off-site Biodiversity Net Gain can be used to meet the requirement by securing biodiversity improvements at an alternative location.
Off-site BNG units are an intended and accepted part of the system and are commonly used where on-site delivery is limited or impractical.
How Biodiversity Net Gain is measured
Biodiversity Net Gain is measured using a standardised biodiversity metric that calculates the value of habitats before and after development.
The metric translates habitat size and condition into biodiversity units, allowing impacts and improvements to be assessed consistently.
Using a standard metric enables developers, ecologists, and local planning authorities to assess BNG requirements in a clear and comparable way.
You do not need to understand ecological theory or metric calculations to engage with Biodiversity Net Gain, provided the process is handled clearly and correctly.
Securing Biodiversity Net Gain
Biodiversity Net Gain must be secured for a minimum period, typically 30 years, to ensure that biodiversity improvements are maintained over the long term.
This is achieved through legal agreements and management arrangements that set out how habitats will be created, managed, and monitored.
For off-site BNG delivery, this includes formally allocating biodiversity units to a development and recording them on the appropriate register.
Who Biodiversity Net Gain affects
Biodiversity Net Gain affects a wide range of people involved in the planning and delivery of development.
This includes developers, home owners, architects, planning consultants, ecologists, and local authorities, each of whom encounters BNG from a different perspective.
While responsibilities differ, the underlying BNG process and planning requirement remain the same.
A clear process makes Biodiversity Net Gain manageable
Although Biodiversity Net Gain introduces new considerations into the planning process, it is not inherently complex.
When approached as a structured, step-by-step requirement, BNG compliance becomes a manageable part of development planning rather than a barrier.
This explanation reflects practical experience across development, land management, and professional ecology.
If you want to understand how Biodiversity Net Gain applies to your role or project, the next step is to look at how the process works in practice.
Simply delivering Biodiversity Net Gain.