Will Local Authority Biodiversity Net Gain targets set new benchmark?

September 4, 2023
In the first of our series of articles on Biodiversity Net Gain (BNG), we explored what is due to happen in November 2023 and how the new 10% biodiversity net gain targets will affect development.

We also discussed how, in anticipation of the minimum BNG standard coming into effect, some local planning authorities (LPAs) have already implemented their own BNG targets as part of local planning policy.

In the second of our series of articles on the issue, Planner, Henry Bourne, explores what BNG policies have been adopted by local authorities in Surrey and Sussex, and what the potential implications are for land promoters in the region.

Some LPAs (14 to be exact) are in the process of setting policies that will require developers to deliver a level of biodiversity net gain (BNG) which exceeds the impeding 10% minimum requirement due to be introduced in November.

But are these local authorities setting a precedence on BNG which developers should aspire to deliver as standard, or are these targets simply isolated examples that developers will need to be aware of on a case-by-case basis?

In Surrey and Sussex, for example, two new BNG policies were adopted in March 2023 which now form part of the Local Development Frameworks for Guilford and Worthing.

It is not impossible that the adopted policies for these two boroughs are used as templates for new local plan policies elsewhere in the country, so, let’s explore them in more detail.

Exploring Local Plans

According to the Guildford Local Plan, development proposals submitted after the national scheme comes into effect will be required to achieve a biodiversity net gain of at least 20%, measured using the national BNG calculation methodology.

Meanwhile the Worthing Borough Council Local Plan (2020-2036), requires a minimum 10% BNG onsite as part of a strategic ecological network with regard to green infrastructure and local nature recovery strategies.

However, where achievable, a 20%+ BNG is encouraged and, indeed, is required on previously developed sites. Major developments will be expected to demonstrate this at the planning application stage using biodiversity metrics, together with a long-term management plan.

Why are higher BNG targets being adopted?

Looking at the planning inspector’s report for the Guildford Local Plan, it is thought that:

  • Evidence on existing and proposed schemes demonstrates that many can deliver 20% BNG on-site.
  • The impact of a 20% BNG policy on viability in Guildford Borough would be marginal and, as such, would not undermine deliverability.
  • There is suitable evidence to show that the availability of off-site units should not be a problem.
  • The local environment is in decline.

Will other Local Authorities follow suit?

It is likely that other local authorities will also be looking to adopt tighter restrictions on biodiversity to promote more sustainable and beautiful development.

The adoption of these policies will give further encouragement to other Local Planning Authorities (LPAs) that a minimum 20% BNG target is a reasonable policy position.

Surrey already has three local authorities including Guildford which are seeking a 20% BNG, and it would not be surprising to see others follow suit.

To justify this approach, Local Authorities will need to provide suitable evidence to demonstrate that any uplift in BNG targets is achievable, showing that:

  • Sufficient land is available to provide BNG improvements at 20%.
  • Previously adopted schemes in the Borough have achieved a 20% gain.
  • The 20% uplift in BNG would not undermine site viability.
  • The local environment requires further protection.

What does it mean for land promoters?

We believe that the inspector decisions in Guildford and Worthing are likely to lead to more LPAs adopting a 20% threshold.

This will essentially make the nationally prescribed 10% requirement a fallback position when a promoter can suitably demonstrate the 20% is not achievable.

Ultimately, what this will mean is that less of the allocated site will be available for development and more schemes will have to adopt a landscape and ecology led design to master planning.

These decisions also raise further questions over site viability, especially when developers are being pressured by increased costs and higher demands for on and off-site infrastructure.

Whilst it is generally accepted that our landscapes and habitats need better protection, a proportionate and considered approach needs to be taken to development.

Henry Bourne, Planner, Vail Williams.
By applying a unilateral 20% BNG requirement to all sites, we fail to recognise that every site is unique and should, perhaps, be assessed on a case-by-case basis instead.

Ultimately, there will come a point where decisions will need to be made on what takes precedence, as sites are going to struggle to meet these ever-increasing demands.

As a result, this will further add to the debate around affordable housing, infrastructure, and ecology. Consequently, this new policy position could result in even more schemes seeking compromise, including on affordable housing provision.

With Guildford set to adopt a 20% minimum BNG target, the planning inspector’s report notes that there will be scope for flexibility in cases where a viability assessment demonstrates the overall scale of obligations threatens scheme viability.

Looking forward, it will be interesting to see how this target is balanced against other competing obligations to determine the way forward for developers and landlords.

If you would like help and support in relation to development and biodiversity net gain – whether you are a developer or landlord – get in touch with our planning team for more information.