A recent appeal decision relating to seven homes on agricultural land beyond the settlement boundary highlights the risk for developers relying on private spaces to generate on-site BNG and the challenges of evidencing existing biodiversity assets where retention is relied on. Non-compliance risks non-consideration of BNG evidence during the planning balance determination.
BNG Requirements
Planning permissions for most forms of development are now subject to a deemed planning permission requiring a net gain in biodiversity relative to pre-development value of on-site habitats (Sch 7A para 2) of at least 10%. This is achievable through onsite or registered offsite gains (often acquired through habitat banks) or statutory biodiversity credits. The BNG condition operates as a pre-commencement and statutorily imposed condition – a BNG Plan must be approved before commencement.
The local authority validated the application on the basis of the submitted Small Sites Biodiversity Metric and a basic BNG Plan (identifying substantial BNG – 120.97% gain in habitat units and 299.44% in hedgerow units, through modified grassland, trees, native hedgerow and a ditch).
Private Gardens
Two flaws in the submitted materials contributed to the decision to refuse permission on appeal:
(1) The Inspector agreed that the baseline habitat assessment and calculated gain was not robust (based on the reliance on vegetation retention);
(2) The BNG Plan itself was undeliverable: most of the modified grassland, trees and native hedgerow were on private garden land. The Inspector accepted that BNG “cannot be legally secured in private gardens” (given the inability to enforce access to monitor and maintain), and so gave no weight to the Plan.
The PPG is clear that BNG should rarely be a reason for refusal, albeit that it notes the need to consider whether the BNG condition is capable of being “successfully discharged” – including conditions requiring maintenance for at least 30 years after completion.
Planning Balance
Given the Council lacked a 5-year supply of housing land, Para.11d of the NPPF was engaged – namely permission should be granted unless “adverse impacts of doing so would significantly and demonstrably outweigh the benefits”, assessed against overall Framework policies. The Inspector considered local amenities and transport links as existent and accessible. This together with quick delivery potential, alleviating “housing shortfall” and resident socio-economic contributions to area services and facilities, attracted “moderate” positive weight.
However, “significant” negative weight was given to conflicts with the NPPF in relation to:
- Character and Appearance – the “fundamental change” of the land use character from open land use to subdivided residential and “uncertainty” of vegetation retention was held to conflict with District and Neighbourhood Plan policies and the development failed to comply with requirements to protect and enhance landscape features;
- Highway Safety – inability for two vehicles to pass without dangerous reversing and uncertainty of track ownership (and therefore of maintenance and upgrading responsibilities) meant the Inspector could not impose a planning condition to secure the upgrade necessary to improve highway safety. Development was found to have an “unacceptable and detrimental impact” on highway safety, thereby conflicting with Policy TRA2 of the District Plan; and
- lacking evidence of biodiversity benefits.
Particularly, Chapters 12 and 15 which promote “good design” as a cornerstone of “sustainable development” and that decisions should “enhance” the natural environment through “net gains”. Moreover, the Inspector noted the Framework guidance that a development’s adverse highway safety impacts justified refusal on highway grounds. The above, alongside the proposal conflicting with the Council’s development plan and not constituting sustainable development, were found to “demonstrably” outweigh development benefits.
Oddities
At one level, this is all fair enough, particularly if:
- a straightforward approach to the character and appearance is taken;
- relatively little weight is given to the need for new homes (despite the established housing need and local failure to meet it);
- the level of biodiversity gain above the mandatory 10% was something that would otherwise have made the scheme acceptable.
At another level, it is surprising in relation to the BNG reasons (setting aside the question of whether the Inspector could simply have imposed a condition requiring the access road to be made up to a specific standard before occupation took place) because:
- the achievement of the 10% mandatory gain is ‘locked in’ by statutorily deemed condition – no development could start until a BNG Plan establishing this had been approved in any event (whether on or off site);
- it would be surprising if BNG above this level would have been much of a differentiating factor in the circumstances.
Practical Issues
Developers should be careful if promoting schemes that rely on BNG:
- in private domestic areas, where little weight may be given in the planning balance for gains above the mandatory 10%;
- where there is ambiguity or technical shortfalls in the baseline condition evidence, particularly where retention of pre-existing biodiversity assets is proposed.
For policy-makers, BNG poses an ongoing challenge in finding the scale of schemes where it makes sense to deliver and maintain. It is not hard to see why far broader exemptions are under consideration as part of the review of the BNG regime.
With thanks to Jonathan Webb for preparing this blog
