A practical guide to Biodiversity Net Gain
We know Biodiversity Net Gain (BNG) can feel like a maze. As landowners ourselves, we’ve had to navigate it too.
This guide is here to simplify what it means, why it matters and how to make it work in practice.
What is BNG?
Why it’s here, and why it matters
How it all works
Onsite vs offsite BNG
The hurdles and the opportunities
The Biofarm Way
What is BNG?
A better way to build
Biodiversity Net Gain (BNG) is a simple idea with big ambition: every new development should leave nature better than it found it.
Since 2024 it has been a legal requirement across England. It means almost all developers applying for planning permission must compensate for habitat loss during their project. Using DEFRA’s biodiversity metric, they must show:
how they will replace lost habitat
how they will create a minimum 10% overall uplift in biodiversity
and how they will keep it thriving for at least 30 years.
This biodiversity gain can be delivered on the development site itself (onsite), somewhere else (offsite), or a mix of both. However it’s done, BNG is an opportunity for nature and development to grow side by side.
Why it’s here, and why it matters
Decades of disconnected development, poor land management and disjointed policy-making and subsidies have come at the cost of nature. Wildlife and plant life have been pushed aside to make way for the homes, schools, roads and more that our communities rely on.
Sadly, almost half of Britain’s natural biodiversity has disappeared. The steepest loss of any G7 country, placing us amongst the worst 10% worldwide (The Guardian). The risk isn’t just environmental, it’s economic. A recent report by the Green Finance Institute (GFI) and WWF warns that nature loss could wipe as much as 4.7% off the UK’s GDP in the next decade. In other words, the cost of inaction will be felt in our markets and daily lives, as well as our landscapes. When nature declines, so does the stability of the systems that we all depend on to live.
The Environment Act 2021, and the mandatory BNG rules it introduced in 2024, is designed to help reverse that trend. By putting measurable value on habitats, BNG makes nature a central part of the planning system. It gives developers and local authorities a clear responsibility, and offers landowners a new opportunity to create long-term value.
Without this legislation, action at such scale simply wouldn’t be happening. As a world leading policy for biodiversity, BNG in England is setting an example that other countries will learn from. It is the start of an exciting shift in creating natural capital markets and beginning to understand the true value that nature brings.
How it all works: turning nature into numbers
Understanding habitat units
BNG works in a currency called habitat units. Using DEFRA’s biodiversity metric, every habitat is scored by size, quality, type and location. Essentially putting a number on its value to the environment. This makes nature’s value easier to understand across industries, and is shaping smarter land choices: protecting the best sites and restoring those with the most potential.
To measure these values accurately, you’ll need an ecologist to assess the site and advise on what’s suitable for the land and development. Get it wrong, and objections, delays, or even reputational damage can follow. Cutting corners may slip through initially, but broken promises come back to bite when habitats fail to deliver years later. It’s about finding honest, high-integrity delivery that works for everyone involved.
Local alignment and long-term management
BNG delivery also has to align with Local Nature Recovery Strategies (LNRS). England has been divided into 48 of these strategy areas. Each identifies where restoration is most needed and where it will have the greatest impact. Aligning habitat units with these priorities helps make sure the gains are not just numbers on paper, but part of a wider recovery effort.
Once created, the law requires that habitats are managed and monitored for 30 years to ensure they reach their target condition. That can be done by the developer, or handed to a land manager. Either way, long-term commitment is non-negotiable.
From habitat units to healthy ecosystems
It may sound like just another box to tick, but these units translate into real-world results. Spaces where wildlife can return, soil can recover, floods are held back, and food security is strengthened. Sometimes rewilding means hands-on, targeted restoration work. Other times, it means stepping back and allowing natural processes to run their course.
Onsite, offsite, or both?
Onsite control
At first, onsite delivery might seem the simplest route, giving developers more control. But when the metric is applied properly, space, viability and long-term management often make that unrealistic.
Offsite delivers more
For many schemes, offsite delivery is often the only way to make the numbers work without sacrificing developable land – and without the headache and time investment of doing it yourself.
According to experts that contributed to the Government’s Environmental Improvement Plan, it could actually give developers a more cost-effective route to compliance, and help position the UK at the forefront of nature markets and green finance (Strutt & Parker).
From an ecological perspective, the report also states that a broader shift towards offsite BNG could deliver better, more meaningful biodiversity outcomes. Habitats created within developments tend to suit species that tolerate human activity. Whereas larger, offsite projects can deliver richer, better-connected spaces where a wider range of species can thrive.
For local planning authorities (LPAs), offsite delivery provides a practical way to meet local environmental objectives, help developers meet their requirements, all without stalling housing targets.
Finding the sweet spot
The real sweet spot is offsite land that’s close to the development, ideally within the same local authority or National Character Area, and aligned with local nature priorities. That way, BNG not only meets policy but delivers tangible gains for the places and communities it’s meant to serve.
The last resort
As a final fallback DEFRA does offer Statutory Biodiversity Credits for developers who can’t secure onsite or offsite units. But it’s a much more expensive route than proactively engaging in biodiversity units, as the price is set to discourage their use.
The hurdles and the opportunities
We understand that BNG adds another layer to an already complex planning process. Governments and planning authorities are being pulled in every direction: build more, cut costs, go green. Developers are stuck in a web of red tape, regulations, rising costs and complex planning requirements. Meanwhile farmers and landowners are being squeezed from all sides with shrinking margins and disappearing political support.
It may feel like a burden, but for developers it has the potential to enhance a project’s reputation and attract investment. For landowners it offers a new way to protect their land and unlock long-term value. Whilst also breathing new life, both economic and environmental, into nature and communities that need it most.
Done well, BNG isn’t another planning hoop, it’s a real chance to leave the landscape in a better state than we found it.
The Biofarm way
At Biofarm, we make BNG work in practice, not just on paper. We deliver fully managed, offsite BNG by transforming unproductive land into lasting habitats. And looking after them for the full 30 years.
Behind it all is a team with deep ecological and commercial experience. At Biofarm, we know the pressures, the pitfalls and the opportunities of this new market first hand. We’re not here to game the system or paper over cracks. We’re here to deliver habitats that work, and value that lasts, in the best way for everyone involved.
Our process
We start by matching the right land to the right project. Our network of landowners means we can deliver habitat units on demand, tailored to the development. We handle the entire regulatory process, take on the long-term management, and keep everything aligned with local and national priorities.
How it plays out
For landowners, it’s a chance to unlock more value from land that’s delivering little today. In the Biofarm model, landowners receive a contribution to the full agricultural value plus a share of the profit from units, all while keeping ownership. Long-term management and monitoring funds are fully ring-fenced, guaranteeing the land is cared for properly over the 30-year commitment.
For developers, it’s a smoother path through the planning process. We handle everything, end-to-end so that they can focus on what they do best.
And for local authorities, it’s robust, policy-compliant delivery that stands up in both planning meetings and on the ground.
To date, Biofarm has:
1,957 habitat units for sale across 767 acres
5,367 more habitat units in the pipeline
393 habitat units already created
7 longhorn cattle, 6 Exmoor ponies and 2 Tamworth pigs working the land
12 team members making it all happen
Looking ahead
BNG is part of a bigger shift towards valuing nature as a form of capital, every bit as real as housing or infrastructure. As we see it, progress should not come at the expense of nature. With the right partnerships, it can mean nature’s recovery too.
But this takes honesty, early engagement and a willingness to do things properly. As the industry finds its rhythm, we hope that best practice will mature, consistency will follow and the benefits will compound over time.
At Biofarm, we’re committed to seeing that through. Working with developers, landowners and local authorities to make BNG not just deliverable, but durable. For the economy, for communities and for nature itself.
Get in touch today to see how BNG can work for you.