Biodiversity Net Gain is one of those phrases that feels simultaneously important and slightly mysterious. Luckily, it’s much simpler (and much more logical) than it sounds.
Here’s a friendly, five‑minute guide to help conveyancers explain BNG clearly and confidently, minus the jargon and the drama.
What is Biodiversity Net Gain?
BNG is now a legal requirement for most land developments in England. In short: Every development must leave nature in a measurably better state than it was before.
That means developers need to increase the biodiversity value of a site by at least 10%, using a recognised metric to show that habitats have been created, enhanced, or restored.
This shift reflects a very practical reality: biodiversity has been declining fast. BNG aims to reverse that trend by embedding environmental improvement into the planning system rather than treating it as an optional extra.
How is BNG measured?
This is where the metric comes in – most notably Defra’s Biodiversity Metric 4.0, the industry’s standard tool for assessing habitat value.
Ecologists (or other suitably qualified professionals) assess:
- the type of habitats on the site
- their condition
- their distinctiveness
- their size
- any linear features such as hedgerows or rivers
Each habitat gets a biodiversity “score,” forming the baseline. Developers then show how they’ll deliver at least a 10% improvement on that score.
In practice, this often requires a site visit, and yes, habitat surveys mostly happen in spring and summer, which adds a fun seasonal constraint to planning teams.
How can developers achieve Biodiversity Net Gain?
There are three main routes:
1. On-site improvements
Enhancing or creating habitats within the development boundary — for example, restoring grasslands, adding woodland areas, or improving connectivity between ecological features.
2. Off-site units
When on-site uplift isn’t possible, developers can deliver improvements elsewhere, sometimes using habitat banks: areas of pre-created, high-value habitat that generate biodiversity units.
3. Statutory biodiversity credits
A last resort, used when neither on-site nor off-site options are feasible. These are government-issued credits, designed to fill unavoidable gaps rather than be a go‑to solution.
Most schemes blend the three to meet their uplift target.
Why does Biodiversity Net Gain matter to conveyancers?
Although BNG primarily affects the planning and development stages, it’s becoming increasingly important in transactions too, especially where:
- land is being sold for development
- development sites change hands mid‑process
- off-site biodiversity units are being purchased or traded
- long-term habitat management obligations (often 30 years) are attached to land
Key considerations include:
- Legal agreements, such as Section 106 obligations securing habitat creation and maintenance
- Land charges that bind future owners to ongoing ecological management
- Liability and stewardship, including who is responsible for monitoring and maintaining habitats over the long term
- Valuation, since BNG potential can inflate or depress a site’s development prospects
A little early clarity can prevent big headaches later.
Is BNG good news?
In a word: yes. It ensures development contributes positively to the environment, encourages smarter land use, and helps protect ecosystems that support everything from pollination to flood resilience.
It also aligns with wider sustainability goals and, increasingly, consumer expectations. Nature recovery is no longer a fringe concern – it’s becoming part of mainstream development practice.
Biodiversity Net Gain is a significant, forward‑looking change to how we plan, build, and value land in England. For conveyancers, it’s another dimension of due diligence – but also an opportunity to help clients understand a major shift in environmental responsibility.
And despite its name, BNG isn’t about hugging trees (though no judgement). It’s about ensuring that development leaves nature better off than it found it – with a clear metric, a legal backbone, and practical pathways to deliver meaningful ecological uplift.
