Business & biodiversity: BNG in England - a Q&A with experts

Under Biodiversity Net Gain (BNG), developers have a clear goal: make sure their projects produce a 10% “net gain” in biodiversity.

Dave Encarnation & Banashree Thapa

Dave Encarnation & Banashree Thapa

04 Apr, 2024

Business & biodiversity: BNG in England - a Q&A with experts

Our previous blog post on

Business & Biodiversity

outlined the crisis nature is facing and the importance of maintaining and restoring biodiversity at local, regional, and global scales. We also discussed the ongoing evolution of biodiversity credits and the role they can play in restoring nature.

In the UK, discussions around valuing biodiversity have resulted in the development of Biodiversity Net Gain (BNG), which refers to a policy approach for establishing and enhancing natural habitats in England. 

What is BNG?

Starting in 2024, England is taking a big leap forward in protecting nature with a new approach called Biodiversity Net Gain (BNG). Simply put, BNG means that any new development project must leave the natural world in a better state than before.

Think of it as giving back more to nature than we take. This rule applies to almost all development projects, big and small, making it a game-changer for the environment.

Under BNG, developers have a clear goal: make sure their projects produce a 10% “net gain” in biodiversity. This means if a new building replaces a wildflower meadow, the developer must find ways to not only replace what was lost but also enhance natural habitat by an additional 10%. This could involve creating new green spaces like forests or meadows either on the same site or somewhere else.

The idea is based on measuring the "biodiversity units" of a site. If a development project causes a loss of these units, the developer needs to make up for it. This can be done right there in the project area or elsewhere. And if they can't meet the 10% improvement target on their own, they can buy "credits" from the government.

These credits fund environmental improvements across the UK, helping to boost nature conservation efforts nationwide.

Who does BNG apply to?

biodiversity net gain construction site

From February 2024, BNG will become mandatory for all major development projects that include the following:

  • Development plans for 10 or more dwellings or on a site having an area of more than 0.5 hectares.

  • All developments of buildings where the floor space to be created by the development is 1,000 square meters or more.

  • Non-residential developments on a site having an area of 1 hectare or more.


BNG wont be applied retrospectively, which means that all planning applications granted to landowners, developers and land managers before 31st January 2024 will be exempt from the BNG regulations. 

BNG isn't just a new policy; it's a potential revolution in funding for nature conservation in England. While the government has provided lots of information for businesses and developers, there's still a lot of discussion about how best to implement BNG.


Asking the experts:

To dive deeper, we talked to two experts in the field who shared their insights and hopes for how BNG can help restore England's natural habitats.

Dr. Joe Bull

Associate Professor of Climate Change Biology at the University of Oxford

Rob Wreglesworth

Associate Ecologist & Innovation Lead at Environment Bank

What excites you the most about BNG?

Joe Bull:

“It is amazing to have a policy not only (a) designed to quantitatively try and deliver a gain in biodiversity (beyond limiting losses), but also that (b) is mandatory and applies to most development projects. Taken together, these make BNG one of the more ambitious national 'net outcome' style policies we have seen so far.”

Rob Wreglesworth:

“Biodiversity Net Gain…is an ambitious and innovative piece of policy which tries to manage the tricky balance of biodiversity loss and infrastructure development. Biodiversity has gradually and consistently been negatively impacted for decades by the development sector, with only limited protected species legislation acting as a last line of defence. BNG finally puts a value on nature, which although is not perfect, is better than how it was valued before in the planning process which was very little, if at all.” 

There is no doubt that assigning a value to biodiversity has already led to changes in the development sector by reinforcing the

mitigation hierarchy.

The “mitigation hierarchy” refers to the strategy of avoiding and minimising negative impacts on biodiversity before purchasing offsets. As mentioned above, BNG in England requires developers to follow this approach, first by minimising habitat and biodiversity losses onsite, followed by on-site habitat improvements, and purchasing offsets as a last resort.

This clearly incentivises developers to avoid high-value habitats (which would require them to spend more money on offsets) and instead conduct business in lower value habitats that are more easily compensated for. 

What concerns you about the roll-out of BNG?

Rob Wreglesworth:

On site biodiversity will have all sorts of pressures from the new development and will only ever benefit a small number of habitats and species. This is a missed opportunity for increasing private sector finance into nature recovery at scale. If we instead took the more holistic view of minimising biodiversity loss and restoring biodiversity in the most impactful areas we could have better outcomes.”

As mentioned above, although BNG is a great first step towards assigning a value to nature and achieving a net positive biodiversity impact of any new developments, it is not a perfect solution. While the mitigation hierarchy is great for encouraging developers to reduce on-site biodiversity impacts, within BNG the mitigation hierarchy prioritises on-site biodiversity actions (e.g., planting a wildflower meadow next to an office park) that must be taken before off-site actions (such as BNG units).

Often, on-site biodiversity actions are limited in scope and scale and this can lead to a patchwork of small, fragmented habitats. By prioritising on-site biodiversity actions, it doesn’t allow us to aggregate resources for large-scale habitat restoration as easily.

If you could choose one thing to improve about the current BNG approach, what would it be and why?

Both experts echoed the concern over the ability of the government and developers to monitor BNG. Being able to track BNG uplift is crucial for bringing the policy-implementation gap and actually delivering a “net gain” for biodiversity and ecosystems. 

Rob Wreglesworth:

The main concern is the quality of the government's digital infrastructure to record and track BNG. The key for this policy succeeding from both a biodiversity point of view and also a trust perspective is that all BNG whether that be within development or as an offset is tracked in a robust, transparent way that can be easily audited and scrutinised.”

Joe Bull:

“We need sufficient capacity/expertise at the LPA [local planning authority] level to ensure BNG is checked and implemented properly in the first place, and we need the BNG register to capture as much information as possible that independent parties/researchers can track and analyse implementation. We could spend all day talking about possible [policy] changes, but at the end of the day, none of it will work unless we get robust monitoring and compliance measures in place.”


Summary and conclusions

biodiversity net gain habitat 1

It is clear that the launch of mandatory BNG in England marks a major step forward in valuing and driving funding to nature conservation and restoration.

However, despite its ambitions, BNG does require improvements, particularly in monitoring and verification. Notably, BNG focuses on the development sector, meaning that a large proportion of companies and institutions are not beholden to it. It also only applies to new developments, and does not account for things like value chain biodiversity impacts.  

This does not mean that these companies do not have biodiversity impacts. On the contrary, it is crucial for all companies to quantify their biodiversity footprint, much as they would quantify their carbon footprint.

When this is done, though, what happens next?

While many companies may not be required to implement BNG, they may nevertheless be interested in mitigating their biodiversity impact. We will discuss all this and more in our next blog post, where we will walk you through voluntary biodiversity contributions and how Earthly will be working to track, monitor, and verify these efforts.