Discharging your BNG Conditions

Most people meet biodiversity net gain as a line in a planning officer’s report and file it under “deal with it later”. The trouble is where the requirement bites.

Planning permissions in England now carry a biodiversity gain condition. It is deemed to be there, and does not have to be written on the decision notice to apply. And it is a pre-commencement condition: you cannot lawfully begin development until the local planning authority has approved a biodiversity gain plan for the site.

So the sequence is not “get permission, then sort out BNG”. It is “get permission, sort out BNG, then start”.

What the gain plan has to show

In outline, four things:

• the pre-development biodiversity value of the site, measured with the statutory biodiversity metric
• the post-development value of whatever habitat you are creating or retaining on site
• any registered off-site biodiversity gain allocated to the development
• any statutory biodiversity credits purchased

Together those have to demonstrate at least a 10% increase over the pre-development baseline. Area habitats, hedgerows and watercourses are demonstrated separately, so you need 10% in each module you affect.

Where the delay usually comes from

Rarely from the arithmetic. Almost always from one of these:

The baseline survey was done in the wrong month. Grassland cannot be condition-assessed sensibly in December. If the metric baseline is challenged and you need a resurvey, you may be waiting for a season, not a fortnight.

On-site delivery turned out to be thinner than the layout suggested. Land that is doing drainage, access and public open space duty is not usually doing much biodiversity duty as well. The shortfall appears late, once the layout is fixed.

Off-site units were left until the plan was being drafted. Units have to be registered on the biodiversity gain sites register and allocated to your development before the plan can rely on them. That is a process with other people in it: the bank operator, the register, sometimes a solicitor. It is not a same-week purchase.

What to do about it

Work out your likely off-site requirement while the layout is still moving, not after it has been fixed. At that stage the requirement is still changeable: a hedgerow retained rather than removed, a scheme boundary drawn slightly differently, a change to the phasing can all reduce what you have to buy. Once the metric is submitted, the number is the number.

If you would rather have an indication early than a surprise late, send us what you have: the site location, the planning stage and whatever metric output exists. Even a rough baseline is enough for us to tell you what is likely to be needed and how we can help.