Large-Scale implementation

Biodiversity Net Gain (BNG) officially landed in February 2024 under the Environment Act. On paper, it’s a simple idea: every development should leave nature better off than before. In practice, that means developers must show a measurable improvement in biodiversity – not just replacing what’s lost, but actually delivering at least 10% more.

At first, the rules only applied to large scale planning applications. Developers could meet the requirement by creating habitats on-site, funding off-site projects, or buying Government statutory credits. For landowners, this sparked real interest – suddenly there was the chance to set up habitat banks and sell biodiversity units, opening up a new natural capital income stream.

Then came the Small Sites

In April 2024, BNG was extended to cover small-scale developments. And the thresholds are tiny: any non-residential project over 25m², or anything impacting more than five metres of linear habitat eg. hedgerow or watercourse, now falls under BNG.

What Does This Mean for Agricultural Development?

In reality, many on-farm projects have very minimal ecological impact. But they’re now caught by the same rules as large commercial schemes. That brings with it hefty administrative, financial, and long-term management obligations. To comply, landowners face maintenance and monitoring requirements lasting a minimum of 30 years.
Projects that used to sail through a straightforward planning process can suddenly become unviable. Why? Because of the disproportionate costs of ecological surveys, biodiversity assessments, mitigation strategies, and, in some cases, offsetting.

Yes, there are exemptions – but in truth, they don’t go far enough. With such a low threshold (just 25m²), almost every new agricultural building outside of permitted development rights is impacted.

And this is happening at a time when farming is already under intense economic pressure. If the Government wants a sustainable farming sector that continues to grow food, then farms must be able to invest. Modern infrastructure whether it be grain storage facilities, slurry stores, silage pits, machinery sheds or livestock housing are essential for growth and ongoing efficiencies. And that’s before we even touch on the effect for possible diversification projects.

What are my options as a landowner?

One possible way through the BNG minefield is to use permitted development rights. These can offer a route around the complexity – but they come with their own strict limits on size, use, and location. In some cases, phasing projects under PD may be a cost-effective strategy to avoid the long-term commitments BNG brings.

The key takeaway? Farmers and landowners should be factoring BNG into project planning much earlier than before. Getting advice from planning specialists at the start can help identify the most straightforward and cost-effective route forward.