Developers in England must now leave nature at least 10 % better off. When they can’t, they buy biodiversity units—and that’s a new income market for farmers.
Why BNG is a big deal 🔍
Before we dive into the numbers, let’s explore why Biodiversity Net Gain (BNG) matters. Simply put, it ensures developers leave the environment measurably better than they found it.
- Guaranteed demand. The Environment Act 2021 makes BNG compulsory for most planning permissions from February 2024.
- Real money. Statutory credits are paid as a one-off fee—no annual receipts—and developers must ensure the habitat meets agreed targets within 30 years.
- Income potential. Even marginal or unproductive land can be enhanced for biodiversity and earn significant one‑off payments.
With demand secured by law, the financial incentives make it worthwhile to turn ecological improvement into an asset.
1. How biodiversity units are calculated
At the heart of BNG is a simple formula that gives every hectare of land an ecological score. This metric guides both planning and payment.
Habitat units = Area (ha) × Distinctiveness × Condition × Strategic significance × Connectivity
By evaluating each factor, landowners can see exactly where to focus improvement efforts.
- Distinctiveness (1–16): How rare or species-rich the habitat is.
- Condition (0.2–1.0): The health and structure of the habitat under current management.
- Strategic significance (1.00–1.30): Whether the site lies in a nationally or regionally important location.
- Connectivity (1.00–1.50): Bonus weight if the area links up with other valuable habitats.
Knowing these values in advance helps plan the most cost-effective enhancement measures.
2. Quick look: Statutory credit prices (updated June 2025)
Prices vary widely depending on habitat type. Here’s a concise table to guide your expectations.
Area-based habitats
| Tier | Example habitat | £ per credit |
| A1 | Low distinctiveness (all) | £42,000 |
| A2 | Woodland & intertidal sediment (medium) | £48,000 |
| A3 | Wet woodland, other high habitats | £66,000 |
| A4 | Ponds (priority), floodplain, maritime habitats | £125,000 |
| A5 | High-distinctiveness lakes | £650,000 |
Area-based habitats form the bulk of BNG credits; deeper pockets may benefit from higher-tier projects.
Linear habitats
Smaller in scale but still impactful, linear features often tie landscapes together.
| Tier | Habitat type | £ per credit |
| H | Hedgerow | £44,000 |
| W | All watercourses | £230,000 |
Note: 2 statutory credits = 1 biodiversity unit (SRM applies). Prices are a last-resort ceiling; private off-site units often trade 10–25% lower.
If you’re considering private trades, remember market rates often undercut these statutory ceilings.
3. Case study: 4 ha corner paddock
Let’s walk through a real example to see how the numbers stack up in practice.
Imagine a 4 ha paddock that currently scores just 3.20 habitat units. With targeted improvements—reducing fertiliser, overseeding wildflowers and adjusting grazing—the same field can rise to 6.40 units. That 3.20‑unit uplift becomes 6.40 statutory credits. At £42,000 each, that equates to a one‑off payment of £268,800.
| Metric | Value |
| Baseline habitat units | 3.20 units |
| Post-improvement units | 6.40 units |
| Net uplift | 3.20 units |
| Credits required (×2) | 6.40 credits |
| Total payment (6.40 × £42k) | £268,800 |
After factoring in modest costs—around £5,000 for seed, fencing and preparation—you still walk away with over £260,000. Not bad for a single field!
4. Five‑step action plan
Ready to get started? Here’s a succinct roadmap from survey to sale.
- Baseline survey. Hire a qualified ecologist to run the metric.
- Upgrade habitat. Reduce fertiliser, add wildflower seed, tweak grazing to raise the condition score.
- Secure the agreement. Sign a 30‑year conservation covenant or Section 106.
- Register & market. List your site on Natural England’s BNG Register and negotiate with developers or brokers.
- Manage & report. Provide evidence every five years to unlock staged payments.
Each step builds on the last—stick to the plan, and the process can become second nature.
Key takeaways
- You don’t need new woodland—improving what you have can unlock serious value.
- Credits are scarce near growth hotspots; location attracts a premium.
- Stack with schemes like the Sustainable Farming Incentive (SFI) where rules allow.
- Start small: trial one field, prove the model, then scale.
With these insights, you’re well-placed to navigate the BNG landscape and secure meaningful returns.
How to monitor your biodiversity in real time
Monitoring doesn’t have to be manual or time-consuming. Modern tech can do the heavy lifting for you.
Item: Section F – Farm bird monitoring equipment (e.g. song meter acoustic detector)
How It Works:
- Deploy at key locations on your farm
- Plug in solar panel for indefinite use, no need to bring in!
- Chirple automatically identifies birdsong and logs them for you
- Data reveals habitat hotspots—guiding targeted wildflower planting and scrub-corridor restoration
- Pre- and post-installation comparisons verify biodiversity gains and support eco-certification
By combining automated monitoring with periodic expert surveys, you can ensure compliance and demonstrate continual gains.
