The Government has announced a series of changes to the way Biodiversity Net Gain (BNG) will be applied to development, with a particular focus on reducing the burden on smaller sites and improving flexibility for off-site delivery. The reforms are expected to have important implications for developers, landowners and planning professionals as the industry continues to adapt to the evolving BNG regime.
To understand what has changed and what those changes could mean in practice, our Planning Design Manager, and BNG expert, William White shares his perspective on the latest reforms, the direction of travel for BNG policy, and the key issues developers should now be considering.
1. Can you start by explaining your role and how it relates to Biodiversity Net Gain (BNG)?
My role involves advising developers and landowners on how Biodiversity Net Gain (BNG) requirements affect their schemes, including viability, planning strategy and delivery. This includes helping clients understand when BNG applies, what their obligations are, whether on-site or off-site delivery is most appropriate, and how to manage biodiversity requirements without delaying projects.
A key part of this is working closely with ecologists and the wider project team at the very outset. Early collaboration allows us to design BNG into a scheme from the beginning, rather than treating it as a constraint later in the process. By integrating ecological considerations alongside layout design, viability and planning strategy, we can identify opportunities to enhance biodiversity in a way that complements development, often ‘double stacking’ land uses to make the most efficient use of space.
As BNG has become embedded within the planning system, this kind of proactive, early-stage approach has become increasingly important. It helps ensure BNG is delivered efficiently, reduces the risk of redesign or delay, and ultimately leads to more coherent, sustainable and practical schemes.
2. The Government has announced some major BNG, can you explain the headline changes?
The biggest headline is the proposed exemption of smaller development sites from mandatory BNG requirements, alongside reforms aimed at making off-site biodiversity delivery more flexible.
The key changes include:
- exempting sites under 0.2 hectares,
- potential exemptions for some brownfield residential developments,
- and improving access to off-site biodiversity units.
Collectively, these changes are intended to reduce barriers to development while retaining BNG for larger schemes.
3. Why does the Government hope to achieve with these changes?
The reforms are largely a response to concerns that BNG, while well-intentioned, has imposed disproportionate burdens on smaller sites.
With these changes, the Government is trying to strike a balance between:
- delivering environmental improvements,
- and maintaining development viability, especially for SMEs and brownfield regeneration.
4. What practical difference will the small site exemption make?
For smaller developers, it could make a really big difference.
Many smaller schemes currently face:
- ecology surveys,
- metric calculations,
- off-site unit costs,
- and planning delays.
Removing those obligations for sites under 0.2 hectares could significantly reduce upfront costs and improve viability, particularly for infill and urban schemes.
5. How important is this for developers?
This is especially important for smaller to medium size developers, because smaller sites make up a large proportion of their pipeline.
For those developers, BNG has often represented a relatively high cost compared to the scale of the development.
The exemption should make smaller projects:
- faster to progress,
- cheaper to deliver,
- and easier to bring forward.
That could unlock sites that might previously have stalled.
6. What are you hearing from developers about these changes?
The reaction is likely to be positive, particularly from SME housebuilders and promoters of smaller sites.
The biggest frustrations around BNG have often been:
- the cost of compliance,
- delays in securing off-site units,
- and uncertainty in local authority interpretation.
These reforms directly address those concerns.
7. What changes are being proposed around off-site biodiversity units?
The Government is also trying to improve how the off-site biodiversity market works.
That should make it:
- easier to secure units,
- quicker to complete agreements,
- and less of a bottleneck for developers.
For medium and larger sites, this could be just as significant as the exemptions, because flexibility in off-site delivery can have a major impact on programme and cost.
8. Does this mean BNG is becoming less important?
Not at all. BNG remains a mandatory requirement for most non-exempt development. What is changing is the proportionality of the system.
BNG should continue to deliver environmental gains, but in a way that is workable and proportionate for different scales of development.
9. How do these changes affect the way developers should approach BNG strategy?
Developers still need to think about BNG early, particularly on medium and larger sites.
The reforms may create more flexibility, but the core questions remain:
- what is the site baseline,
- how much gain is needed,
- and what is the most efficient delivery route?
Early strategy is still critical to avoid unexpected cost and delay.
10. What opportunities do these reforms create for developers?
There are a few major opportunities:
- Improved viability for small sites
- Greater flexibility for larger schemes
- Potential acceleration of planning decisions
- Reduced reliance on expensive statutory credits
For developers with constrained sites, especially brownfield land, these changes may open up schemes that were previously marginal.
11. Are there still risks or uncertainties developers need to watch?
Yes. Some elements still need to be worked through. There may still be uncertainty around:
- the final scope of exemptions,
- timing of implementation,
- and how local planning authorities apply the changes.
Developers should avoid assuming the reforms remove all BNG risk.
12. What should developers be doing now?
Developers should be reviewing their pipelines to identify:
- sites that may become exempt,
- schemes that could benefit from easier off-site delivery,
- and projects where strategy could be revised.
This is also a good time to revisit cost assumptions around BNG and reassess delivery options.
13. From your perspective, what do these changes suggest?
This reform suggests that the Government is acknowledging that BNG implementation has created friction in the planning system.
This announcement suggests a move toward a more pragmatic and development-focused approach, while retaining the broader environmental objectives.
That is likely to be welcomed across the development sector.
14. What is your key take away for developers?
The key takeaway is that BNG is still a major consideration, but the rules are becoming more flexible.
Developers who understand these reforms and adapt their strategy early will be best placed to benefit from:
- lower costs,
- fewer delays,
- and improved viability.
The opportunity now is to take advantage of the greater flexibility while continuing to plan proactively.
In summary
While the latest reforms suggest a more pragmatic approach to Biodiversity Net Gain, they also reinforce the importance of understanding how environmental policy continues to shape the development process. For many developers, the changes may offer welcome flexibility, particularly on smaller and more constrained sites, but BNG remains a significant consideration for most schemes.
As highlighted, the developers who are best placed to respond will be those who understand the changing policy landscape and incorporate biodiversity strategy into projects from the outset. With further changes still expected, staying ahead of the detail will remain essential in delivering viable development while meeting evolving environmental requirements.
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