Biodiversity Net Gain is now mandatory. Is your evidence ready for inspection?
Biodiversity Net Gain has changed the evidential burden around development in England.
For relevant planning permissions, the statutory objective is at least a 10 percent increase in biodiversity value, measured against the pre-development value of the onsite habitat. The formal process also requires a Biodiversity Gain Plan before development begins, unless the development is exempt.
For landowners and estates, that makes evidence capture an operational requirement.
You cannot inspect habitat improvement that was never properly recorded.
The BNG evidence problem
BNG depends on baseline, calculation, enhancement, maintenance, and monitoring. It is not enough to say land will be improved. The improvement needs to be measured, planned, secured, and evidenced.
That creates a long-duration evidence obligation.
| BNG requirement | Estate evidence needed |
|---|---|
| Pre-development value | Habitat survey, metric tool, date, maps, supporting evidence |
| Proposed gain | Design, enhancement plan, projected post-development value |
| Offsite allocation | Registered offsite gain record and allocation details |
| Maintenance and monitoring | Management plan, responsible parties, inspection records |
| Degradation history | Evidence of condition before any relevant degradation |
Why early capture matters
GOV.UK guidance makes clear that the pre-development biodiversity value is central to the calculation. If surveys are stale, if habitat condition has changed, or if supporting evidence is missing, the estate’s position weakens.
For estates with multiple development opportunities, BNG should not be handled one application at a time. It should be managed as a live evidence layer across the landholding.
That layer should know which parcels have baseline records, which habitats are changing, which opportunities may support onsite gain, and which obligations are already committed.
AI as BNG operating support
Agentic AI can help by maintaining the evidence register, prompting for survey updates, linking maps to parcels, extracting obligations from planning documents, and preparing draft evidence packs for professional review.
It can also flag risk before an application is submitted:
- missing baseline evidence
- outdated surveys
- unclear habitat boundaries
- incomplete metric files
- weak monitoring arrangements
- unrecorded degradation concerns
The AI should not replace ecologists or planning professionals. It should make sure their work is structured, findable, and inspection-ready.
Sources
See GOV.UK guidance on understanding biodiversity net gain and GOV.UK statutory biodiversity net gain guidance.