Need a biodiversity net gain plan in London?

Biodiversity Net Gain London

The biodiversity net gain bng concept has been introduced to reduce the decline in the current state of UK biodiversity. New rules now make it mandatory for planning projects to deliver net gains to the natural world and anyone seeking planning permission must demonstrate that new developments will not adversely affect the environment.

All local authorities across Greater London and the City of London will require biodiversity net gain plans to provide clear evidence that development proposals comply with the policy.

Biodiversity net gain and nature recovery

According to UK government guidance, mandatory net gain aims to leave wildlife habitats in a `measurably better state’ than before the development.

The Environment Act 2021 introduced the biodiversity net gain policy which has an important role in protecting the natural environment from the damaging effects of new development work: schemes must now ensure that on completion, the environment has been significantly improved from its original condition. The biodiversity value must be retained and improved by a minimum of 10% in the biodiversity net gain plan, and the upgraded area must be maintained for at least 30 years.

Following a two year transition period to allow developers and local planning authorities time to attain a better understanding of the system, mandatory biodiversity net gain was introduced on 12 February 2024 for major development on most sites, and after 2 April 2024 for small sites. This has led to local planning authorities requiring a biodiversity net gain plan to provide evidence of how a scheme will create biodiversity to accompany most new planning applications. Biodiversity net gain principles are expected to extend to nationally significant infrastructure projects from November 2025.

As there are few specific exemptions, a biodiversity net gain plan is a mandatory requirement for most development projects in England; refusal to comply with the policy could result in delays or local councils imposing penalties.

Off site biodiversity gains

Three options exist for delivering net gain to ensure a development meets the criteria. While delivery of on site gain is the preferred option, where it’s impossible to achieve gains on the site through land management changes, delivery of off site biodiversity units is permitted, or as a last resort, a private market exists for those needing to buy statutory biodiversity credits.

London’s approach to Biodiversity Net Gain

A new edition of the London Plan which manages development for the area over the next 20-25 years, was drawn up by the Greater London Authority in 2021. Key aims include urban greening by developing green infrastructure, increasing biodiversity, and creating resilient places to live and work. It states that greening must be a major element of urban development proposals across Greater London councils.

Sites of Importance for Nature Conservation contain London’s key wildlife places and the London Plan requires them to be protected by the London boroughs; nearby development must add to the area’s biodiversity value before there are planning permissions granted. Local Nature Recovery Strategies must also be considered in planning applications to London councils.

The Mayor of London and the London Wildlife Trust published Urban Greening for Biodiversity Net Gain: A Design Guide in 2021, highlighting the need to protect London’s green spaces, combat climate change, and strengthen ecological networks. It states that good design approaches are crucial to creating resilient places and making space for nature: simple design considerations include planting trees and installing green roofs. Nature must be at the forefront of development decisions to ensure there are areas where biodiversity can thrive alongside development: often this is possible by habitat creation nearby and creating a mosaic of interconnected green spaces early in the planning process to aid nature recovery in the coming years.

Assessing biodiversity value

A bng survey must be conducted by a professional ecological consultant, who will make a physical inspection of the ecological features present within the red line boundary of a development site. Information on habitat categories will be entered into the statutory biodiversity metric, and by comparing data on the current number of biodiversity units with the anticipated changes to the site at the conclusion of the development, the change in the site’s biodiversity value can be calculated.

The difference between these two measurements must be bridged to ensure the site achieves its pre-development biodiversity value reading, which must then be uplifted by a 10% gain in biodiversity. This can be calculated by reference to the bng mitigation hierarchy. The findings from this exercise will enable the consultant to draw up a biodiversity gain plan for the development site.

A biodiversity gain plan will give the relevant local planning authority the information needed about individual sites to enable them to grant applications for planning permissions. Plans might include details about new habitat creation to enhance biodiversity and meet the uplift requirement of at least 10% according to the biodiversity metric. Adding biodiversity gain may involve changes to the way a land manager maintains the site, or simple measures such as tree planting.

If it proves impossible to provide significant biodiversity gain on the site, the bng plan will outline the methods of purchasing biodiversity units or achieving off site net gain: a legal agreement will be required in this case to stipulate the land management strategy over the 30 years.

Arranging a biodiversity net gain survey

Engaging an ecological consultancy that employs fully qualified ecologists with experience in completing biodiversity net gain plans for the relevant local planning authority is crucial. Having chosen a trustworthy firm, you can rely on their expert advice on how to deliver net gains to enable you to meet your bng requirements and leave the natural environment in a measurably better state.

Having a well designed biodiversity gain plan will give your development proposal the best chance of achieving planning permission.