TP Explainer: Government BNG consultation

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The Department for Environment, Food and Rural Affairs (DEFRA) are currently consulting on proposals to improve the implementation of biodiversity net gain for minor, medium and brownfield development – ‘Improving the Implementation of Biodiversity Net Gain (BNG) for Minor, Medium and Brownfield Development’

The statutory Biodiversity Net Gain (‘BNG’) requirement came into force in the English planning system in February 2024, seeking to ensure that habitats for wildlife are left in a measurably better state than they were before development took place. As a result, it is now mandatory under Schedule 7a of the Town and Country Planning Act 1990 for relevant developments to deliver a 10% BNG on the value of all habitats within a redline application boundary.

In our experience, whilst the objective of BNG is laudable, during the 17 months since its introduction, the operation of the system has been somewhat less than satisfactory, leading to considerable delays in obtaining planning permission, particularly for smaller schemes.

The current consultation seeks views on various options to improve the implementation of BNG for relevant developments, including extending exemptions to the requirement for BNG, simplifying the small sites metric and easing access to the market for off-site provision of BNG.

In particular, the main proposals are as follows for ‘exemptions’ to BNG –

• Introducing a single-dwelling exemption to replace the custom/self-build exemption

• Increasing the de minimis threshold from 25 sqm to options like 50 sqm, 100 sqm, or 200 sqm

• Exempting temporary developments (up to 5 years)

• Considering exempting all but major developments, reverting to pre-April 2024 rules

  
  

In addition, the proposals for BNG ‘adjustments’ for minor development (up to 9 houses/ up to 0.5ha for housing proposals or up to 1,000m2/ up to 1ha for non-residential schemes), can be summarised as follows

• Treating on-site and off-site BNG equally (relaxing the biodiversity gain hierarchy)

• Removing the distance penalty for off-site compensation

• Relaxing trading rules for some minor development

• Allowing local authorities discretion to disapply BNG for watercourses in specific cases

  
  

For medium development proposals (for housing, development where 10 or more houses are proposed/ site area over 0.5ha, and for non-residential development additional floorspace of 1,000m2 or more/ 1ha or more), the consultation proposes –

• Simplifying BNG requirements for sites with 10–49 homes or up to 1 ha

• Improving access to off-site biodiversity units

• Adjusting the Small Sites Metric to better reflect medium-scale development

  
  

Finally, the consultation proposes the following in respect of brownfield development sites -

• Updating the definition of Open Mosaic Habitat (OMH)

• Allowing alternative compensation arrangements for OMH impacts

• Tailoring metrics to reflect unique ecological challenges of brownfield sites

  
  

In addition, there are proposals to boost the off-site market as follows -

• Increasing ease of access to off-site biodiversity credits

• Removing location-based penalties for small developers; and

• Encouraging investment in habitat banks and nature recovery projects

  
  

Tyler Parkes is pleased to see the Government’s proposals to find a pragmatic way forward to balance the needs to deliver development whilst enhancing biodiversity. We welcome the introduction of more proportionate requirements for smaller applications.

If you would like us to assist you with representations to the consultation, please do contact our Planning Team. If you have any questions, or have a scheme that requires BNG input, call us to discuss!

The consultation closes on 24^th July 2025.