An initial BNG assessment is commonly submitted in the early stages of a planning application. This is generally enough to obtain the permission, but the more detailed requirements of BNG should not be overlooked.
There is now an automatic statutory condition for a "BNG plan" to be approved prior to commencement of any new development (or each phase of a phased development). In order to fulfil this councils require both a "Habitat management and monitoring plan" (HMMP) and a completed biodiversity metric.
The HMMP must contain:
- The details of the works that will be undertaken to improve BNG
- The details for maintaining these works for 30 years
The biodiversity metric must be completed using the details for the works contained in the HMMP. This will produce an exact figure for the amount of biodiversity units created by those works.
Councils are under a statutory obligation to ensure that the BNG for each development is secured before approving the BNG plan. This must be done via condition, s106 or conservation covenant.
Common problems with this include:
- If BNG details are not finalised before planning is granted the council may require a separate s106 agreement later to bind the land to those works (particularly if any of the works are off-site)
If the HMMP & Metric are available before grant then these details can be secured in the main s106 for the development.
- Conversely, if biodiversity unit figures have been estimated in initial assessments (or if the metric has been completed but the HMMP is not yet final) councils may insist on including these exact figures in the main s106 agreement
This needs to be resisted as even a small change to the works will produce a different BNG unit figure once the final metric is run.
Therefore even though it is possible to leave BNG details until after the grant of permission it is still preferable to finalise these details prior to grant where possible.
