While Biodiversity Net Gain (BNG) has been mandatory for many developments in England since 2024, from 2 November 2026 the requirements will also extend to Nationally Significant Infrastructure Projects (NSIPs) applying for a Development Consent Order.

For developers, biodiversity needs to be considered early in the planning process, including how the value of a site is measured, whether gains can be delivered on site and when off-site units may be needed.

BNG is a planning requirement designed to ensure development leaves biodiversity in a measurably better state than before.

If a new development results in a loss of biodiversity, developers need to compensate for that impact by creating or enhancing habitat to deliver an overall increase in biodiversity value. This can be achieved within the red line boundary of the development or through off-site habitat, with Local Nature Recovery Strategies (LNRSs) helping identify areas where habitat creation and enhancement can make the greatest contribution to local nature recovery.

So, for example, if trees needed to be cut down to make way for a new building, developers must offset this loss by investing in the creation or enhancement of woodland and its long-term protection in a habitat bank.

In England, the government has set a rule that it is not enough simply to replace and increase biodiversity that will be lost. The biodiversity value must increase by at least 10% compared with the pre-development baseline.

On top of this, any habitat created or enhanced for BNG must be legally secured, managed, and maintained for a minimum of 30 years to ensure long-term ecological recovery.

In practice, meeting the 10% requirement could involve replacing an area of low-value grass with native grasses and perennial wildflowers. A conventional grass lawn typically has limited ecological value, while more diverse planting can introduce greater species richness and provide food and habitat for wildlife such as bees, butterflies and other insects. 

Putting a value on biodiversity is quite complex. However, the UK government has created a Statutory Biodiversity Metric Tool to make sure all developers are working to the same standard.

Different qualities of the land are used to assess biodiversity, including how big it is, what kind of habitat it is, how healthy it is, and where it is located. An ecologist will collect this data and then input it into the tool which will output the value in biodiversity units.

Biodiversity units are broken down into three distinct categories:

• Area Units for fields, woodlands, wetlands, and structural developments
• Hedgerow Units for trees and hedgerows
• Watercourse Units for rivers, streams, and canals.

Ultimately, biodiversity value tells developers what is present before development and the metric helps establish what needs to be delivered afterwards to achieve the required 10% gain.

BNG needs to be considered early in the development process.

An ecologist or other competent professional will assess the existing habitat and use the statutory biodiversity metric to understand the biodiversity value of the site and the likely impact of the proposed development.

For developments going through the town and country planning system, once planning permission has been granted, a Biodiversity Gain Plan (BGP) must be submitted to the local planning authority, setting out how the development will meet its BNG requirement. The plan must be approved before development can commence.

Where significant habitat is being created or enhanced, a Habitat Management and Monitoring Plan (HMMP) can set out how the habitat will be managed and monitored over the long term, including who is responsible for delivering the work.

Developers have three main options for meeting their BNG requirements. They can deliver gains on site, use registered off-site gains or, as a last resort, purchase statutory biodiversity credits.

Where possible, gains should be delivered within the development itself through measures such as wildflower areas, ponds, woodland or another suitable habitat.

If the full requirement cannot be achieved on site, developers can use off-site provision, including biodiversity units from habitat banks where land is being restored or enhanced to create measurable gains.

This is where we can support developers. Through our range of solutions, including on-site BNG design, a network of habitat banks, and soil recycling facilities, we can work with development teams to identify suitable provision to meet BNG based on the requirements of the project.

There is a huge opportunity for developers to move beyond adhering to government rules and instead choose to make an active investment in nature.

By partnering with us, developers can access off-site biodiversity units through habitat banks designed to support long-term nature recovery as well as the requirements of their project.

We work alongside development, ecology and planning teams to help make the process as straightforward as possible, with clear information on the units available, the habitats being created or enhanced and how these will be managed over the long term.

This gives developers confidence that their BNG investment is supporting meaningful habitat creation while helping them meet the needs of their development.

Contact us to discuss your BNG requirements and the biodiversity units currently available.