London BNG Expertise: Over 20 Assessments in the Last Year
The introduction of mandatory Biodiversity Net Gain (BNG) has created a significant challenge for London developers: how to achieve the required 10% gain within the confines of a highly constrained, urban environment. At SWEL, we have rapidly mobilised our ecological expertise to meet this demand, completing over 20 BNG assessments across various London boroughs in the last year alone.
Top Tip: Please don’t do any site clearance works before you have spoken to our ecologists. It could cost you a great deal of money if chop down a valuable tree (£25,000 per tree).
This hands-on experience has equipped us with the proven strategies needed to navigate the complexities unique to the capital. While many developments have zero or low ecological baselines, the London Plan demands meaningful contributions to green infrastructure. Our track record shows we successfully apply the statutory Defra Metric to urban sites, identifying creative solutions such as:
- Urban Greening Factor (UGF) Integration: Ensuring BNG designs complement and achieve the borough’s Urban Greening Factor targets.
- Green Roofs and Walls: Maximising ‘high distinctiveness’ habitats in limited space.
- Off-site Unit Planning: Securing and allocating registered off-site BNG units where on-site delivery is not physically possible.

Example Plans Created by SWEL’s Ecologist
Rapid Response: Qualified Ecologists Ready for Your Project
We understand that delays in planning can be costly. The challenge faced by many Local Planning Authorities (LPAs)—which often lack the in-house ecological expertise and are reporting staff shortages—can slow down the BNG verification process.
To directly address this speed bottleneck, SWEL has a dedicated team of suitably qualified proactive and personable ecologists standing ready to deliver your assessment on a rapid turnaround. Our experts are proficient in the latest statutory metric and the nuanced requirements of individual London Boroughs. By submitting a robust, accurate BNG Assessment and Habitat Management Plan (HMP) from day one, we help your application move through the system efficiently, avoiding unnecessary requests for further information and reducing your time to consent.
On-Site Mitigation?
Our service goes beyond simply calculating your Biodiversity Net Gain (BNG) deficit; we provide comprehensive strategies for achieving the mandatory 10% net gain, regardless of your site’s complexity. We offer expert advice on both on-site mitigation—designing and integrating ecologically valuable habitats such as green roofs, sustainable drainage features (SuDS), and enhanced landscaping directly into your development plans—and securing off-site BNG credits. Whether your London site is too constrained for on-site delivery, or you need a rapid solution, we guide you through the process of legally purchasing and allocating credits from registered off-site providers, ensuring your project achieves the necessary net gain quickly and compliantly for local authority approval.

Another Example Plan From a BNG Assessment
In conclusion, partnering with Southwest Environmental for your London Biodiversity Net Gain assessment delivers both unrivalled expertise and critical efficiency. Our proven track record of successfully navigating over ten complex BNG assessments in urban settings over the past year, combined with our strategic advice on both on-site design and off-site credits, ensures a compliant and pragmatic path to planning consent. When time is money and regulatory detail is paramount, trust SWEL’s team of qualified ecologists to provide the rapid, robust, and reliable BNG solutions you need to keep your London development on schedule and ethically sound. Contact us today to secure your swift BNG assessment.