Baker Consultants

Biodiversity Net Gain

BNG calculation, creation and management

Biodiversity Net Gain (BNG) is the requirement for most new developments to deliver net gains for wildlife. After the Environment Bill was granted Royal Assent on Tuesday 9 November 2021, it is now clear that there will be a legal requirement for developments to secure a 10% net gain. BNG is calculated using the DEFRA Metric 3.0 which takes a measure of the current biodiversity of the site and calculates the scale of habitat creation that will be required to balance that loss plus a 10% increase.

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What's the cost?

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.’

Biodiversity Net Gain

Why Baker Consultants?

Baker Consultants has a long track record of BNG delivery with some projects having been tested at public inquiry. We have considerable expertise in baseline assessment and minimising the cost of BNG delivery. In one case we saved the developer £500,000 simply by looking at alternative ways of delivering BNG.

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Our services

Take a look

Species and Habitat Surveys

Wildlife is not a barrier to development.


Habitat Regulations Assessments

Our team of highly skilled ecology consultants has a reputation for innovation...


Land acquisition

Understand the ecological constraints of your development site.


Environmental Impact Assessments

No planning without EIA.


Preliminary Ecological Appraisal

A first look at your development site.


Planning submission/Public inquiry

Ecologists form part of your development planning and public inquiry team.