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Biodiversity Net Gain (BNG) is a new process designed for the planning system to ensure that development delivers a net positive impact on the natural environment. It requires new developments to be designed and planned in ways that minimise any loss and damage to existing habitats, and then to compensate and off-set any damage caused. This could include creating new habitats.

Biodiversity Net Gain is defined as the achievement of measurable gains for biodiversity through new development i.e. biodiversity is left in a measurably better state than before development commenced.

The delivery of BNG for all major developments is now a mandatory requirement of the planning system (this came into effect on 12 February 2024), excepting Nationally Significant Infrastructure Projects which will require BNG from 2025. This will apply to non-major applications from 2 April 2024.   It will be unlawful to issue a planning approval for any qualifying development that does not secure a minimum 10% Biodiversity Net Gain, with 30-year management and monitoring. There are some exemptions to this requirement: Biodiversity net gain: exempt developments - GOV.UK (

Biodiversity Net Gain is calculated using the statutory biodiversity metric which is available from the government website; a completed version needs to accompany all major applications. You can choose to use a simpler version, the Small Sites Metric, for all non-major applications, as long as there are no European protected species, protected sites or priority habitats (excluding some hedgerows and arable field margins) onsite: Statutory biodiversity metric tools and guides - GOV.UK (

Devon County Council has produced guidance relating to BNG. Please refer to the Devon County Council website for further details: Biodiversity Net Gain - Environment (

Please refer to Local Validation requirements Biodiversity Net Gain - MIDDEVON.GOV.UK

  • Mid Devon District Council require a completed Devon BNG Statement for Validation to accompany every application.
  • Please also note the preferred option is that you provide a map as a separate PDF and not embedded in the metric.


Biodiversity Gain Plan

What must be included in a Biodiversity Gain Plan?


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