Planning and building control

Biodiversity net gain (BNG)

Biodiversity net gain is an approach to development that ensures the natural environment is left in a measurably better state than it was before development took place.

It is a legal requirement, under the Town and Country Planning Act, that developers must prove they are increasing the biodiversity value of a site by at least 10%, unless exempt.  This will be measured using the DEFRA biodiversity metric, that assesses habitat size, quality and location.

Any significant created or enhanced habitat must be managed and maintained for at least 30 years.

If your proposed development is subject to biodiversity net gain requirements, you'll need to include sufficient ecological and BNG documentation at validation stage, before any work starts.

Exemptions

The biodiversity net gain condition does not apply to the following types of development:

  • householder applications (extensions, conversions, for example)
  • biodiversity gain sites - where habitats are being enhanced for wildlife
  • small scale self-build and custom housebuilding
  • 'De minimis' development impacting habitat of an area below a threshold of 25 square metres - for example, five metres by five metres.

One small tree is assigned an area of 41 square metres on the statutory metric. If any development that would otherwise be 'de minimis' involves the loss of such a tree, it would not be exempt from the biodiversity net gain requirement.

Documents you need to provide

There are minimum national information requirements, but we also have additional local requirements for Liverpool, which are detailed below. If you don't provide the information we need with your application, it will be invalid.

1. Biodiversity checklist

 This identifies the ecological information required to support the application, including survey needs, habitat details, and whether biodiversity net gain applies.

 2. Draft biodiversity gain plan

 Your draft gain plan must include:

  • Baseline biodiversity value
  • Proposed habitat retention, creation, or enhancement
  • Calculation showing at least 10% uplift
  • Confirmation that the statutory biodiversity metric has been applied
  • How the mitigation hierarchy has been followed and if the application will require any off-site gains.

3. DEFRA biodiversity metric spreadsheet

The full metric must be submitted as an Excel spreadsheet with macros disabled. Summaries are not accepted.

4. Habitat baseline plan

A plan showing the existing habitat compartments marked with habitat reference number from the last column of the metric baseline (for cross reference).

5. Post-intervention habitat plan

A plan showing retained, enhanced, and newly created habitats marked with the habitat reference number from the last column of the metric creation/enhancement tabs.

6. Condition assessments

Condition assessments are required for each applicable habitat parcel.

Monitoring fees

Any planning applications where biodiversity net gain involves on site significant ecological enhancements will be subject to a s106 legal agreement and monitoring fees. This fee is in addition to the standard 15% fee, should other non BNG planning obligations be secured for the same planning application.

Delivering biodiversity net gain

BNG can be delivered on site, off site or via statutory biodiversity credits.

On site delivery

This is the preferred approach. Enhancements should be incorporated into the site design wherever feasible.

Off site delivery

If on site delivery cannot achieve 10% BNG, you must:

  1. Prior to determination: Provide clear justification in the draft gain plan, in line with the BNG hierarchy site land.
  2. Discharge of conditions: Identify the gain site (off site) and details of proposed enhancements both on a revised metric and on the final biodiversity gain plan.

Statutory biodiversity credits

These should only be used when on site and off site options are demonstrably not possible or where small amounts of biodiversity units (less than 0.25 units) are required for the development to achieve the 10% gain.

You must provide evidence of at least three gain sites that have been approached, and the relevant units are not available before the statutory credits will be accepted.

Further guidance

Merseyside Environmental Advisory Service (MEAS)

MEAS provides technical guidance covering:

  • Survey expectations
  • Condition scoring methods
  • Habitat classification
  • When specialist species surveys or ecological inputs are required
  • Significant and non-significant enhancements

Developers should review these documents early in the design process to avoid delays.

Local Nature Recovery Strategy (LNRS)

The Liverpool City Region LNRS provides:

  • Baseline habitat mapping
  • Priority habitat and species objectives
  • Strategic opportunities for nature recovery

BNG proposals should align with these priorities and integrate local ecological opportunities wherever possible.

Biodiversity net gain policy advice note

Habitat banks

We are considering four sites to develop gain sites to facilitate off site biodiversity net gain. We will provide further details in due course.

Biodiversity reports

The policies and actions we have in place to comply with our biodiversity duty, and what we are doing to improve the environment.