What Is Biodiversity Net Gain (BNG)?

Biodiversity Net Gain (BNG) is a planning requirement in England that ensures new developments leave the natural environment in a better state than before. Instead of simply protecting what’s already there, BNG asks developers to enhance habitats — creating measurable improvements for wildlife, plants, and ecosystems.

BNG became mandatory under the Environment Act 2021, and most developments now need to deliver a minimum 10% net gain in biodiversity to secure planning permission.

Nature in the UK has been declining for decades. BNG is designed to reverse that trend by ensuring every development — from housing to infrastructure — contributes positively to the landscape.

It creates a future where development and nature can thrive side by side.

BNG uses a standardised metric to measure the biodiversity value of a site before and after development. This value is expressed in biodiversity units.

Developers must:

• Assess the existing habitats
• Avoid and minimise harm wherever possible
• Enhance or create new habitats on‑site
• If needed, purchase off‑site biodiversity units to reach the required 10% net gain
• Commit to 30 years of management and monitoring

This ensures long‑term, meaningful ecological improvement — not just short‑term planting.

Develops can meet their BNG requirement in two ways:

1. On-Site BNG

Enhancing or creating habitats within the development boundary. This is often the preferred route but isn’t always possible due to space or design constraints.

2. Off-Site BNG

Purchasing biodiversity units from landowners who have created high‑quality habitats elsewhere. This provides flexibility for developers and new income opportunities for landowners.

BNG is now a requirement for:

• Developers — needing compliant, timely solutions
• Landowners — able to create habitats and sell biodiversity units
• Local authorities — responsible for approving BNG plans
• Ecologists and consultants — delivering assessments and monitoring

BNG isn’t just about compliance — it creates real, lasting value:

• Healthier, more resilient ecosystems
• New habitats for wildlife
• Greener, more attractive developments
• Long‑term environmental stewardship
• New revenue streams for landowners
• Greater certainty and transparency in planning