Biodiversity Net Gain

BNG is one of the most significant changes in wildlife law in the last 30 years and will create a new market in biodiversity ‘units’. Measuring and securing BNG requires expert ecological knowledge firstly to measure the value on site but then to work out how the required 10% gains can be achieved and delivered.

However, the secondary legislation which will implement BNG has not come forward and therefore the legal requirement for a 10% net gain is not yet in place. The decision re: the level of BNG needed for planning applications is therefore presently being decided under the prevailing planning policies that are currently in place.

The National Planning Policy Framework (NPPF) as currently drafted, seeks to ensure that plans should enhance biodiversity and secure ‘measurable net gains’ (para 179). The NPPF does not however define the quantum of gain that should be secured. Many local plans are however currently being updated to reflect the Environment Act 2021 and are setting out the requirement for development to secure at least 10% net gain, referencing the DEFRA Metric as the means of measurement.

Applications stuck in this no-man’s land between the emerging law, which is incomplete but has a clear trajectory, and the published NPPF and local plan policies are currently being played-out in planning decisions and inquiries. The current situation was explored in the recent appeal decision at Malmesbury (see attached appeal decision decided on 5th January 2022). In paragraph 41 of the report, the inspector summarised the current position ‘The Environment Act 2021 has now passed, secondary legislation is required for it to be implemented. Therefore, the 10% biodiversity net gain requirement set out in the Act is not yet law and is not applicable to these appeals. Policy CP50 of the CS [Core Strategy], and Paragraph 174 of the Framework, both seek a net gain in biodiversity without identifying a specific percentage. A net gain of just 1% would be policy compliant in these circumstances. This could be secured by a planning obligation.’