Planning applications now required to deliver Biodiversity Net Gain of at least 10%

Government has adopted a new approach to development called Biodiversity Net Gain (BNG) as part of the two-year transition period following the enactment of the Environment Act (2021). The BNG rules apply to all new planning applications for major developments as of 12 February 2024. They will also apply to new planning applications for certain small developments from 2 April 2024.

The BNG rules aim to ensure that biodiversity value is measured as part of the planning application process and that any new major development leaves habitats for wildlife in a better state than they were before the development. The rules require all new planning applications for major developments to deliver at least 10% biodiversity net gain. 10% BNG is required whether or not the development impacts existing biodiversity.

Developers must maintain the habitats created or enhanced for a minimum of 30 years. This applies to off-site gains or significant on-site gains. Developers can find out more about what must be done in order to meet BNG requirements on the webpage.

What this means for our planning application process

The introduction of BNG means that any such application submitted to the Council of the Isles of Scilly will need to include a completed BNG metric and Biodiversity Gain Plan in order to achieve validation.

The BNG metric is issued by the Department for Environment, Food and Rural Affairs (DEFRA) and must:

  • achieve a minimum 10% gain for habitats, hedges, and rivers (if applicable to the development site). Development features which count towards on-site net gain include SuDS (Sustainable Drainage Schemes), ponds, parks and perimeter hedges.
  • be completed by a competent and suitably qualified ecologist.

If developers cannot achieve all of their BNG on-site, they can deliver through a mixture of on-site and off-site. If developers cannot achieve on-site or off-site BNG, they must buy statutory biodiversity credits from the government. This off-setting should be a last resort. The government will use the revenue to invest in habitat creation in England.  

The Biodiversity Gain Plan must:

  • set out how the metric will be delivered over the 30-year post development period.
  • be produced by a competent and suitably qualified ecologist.

Full details of exactly what these documents need to include and how to develop and submit them can be found on our website.

BNG mandatory for small sites from 2 April 2024

Small developments are currently exempt from the BNG rules. However, the BNG will become mandatory for minor sites on 2 April 2024. This means that developers of small sites (including single new dwellings but excluding householder applications for things like extensions, loft conversions etc) will be required to complete the Small Sites Metric and submit this with their planning application. The Small Sites Metric is a simplified version of the metric used for major applications and is also issued by DEFRA.

Further information

If you have any questions about BNG rules which are not addressed by the links in this news item, please call the planning team on 01720 424456 and leave a message with your name and number so we can call you back.

Publishing date: 
Friday, 23 February, 2024