Habitat Banking Under Scrutiny: Operational Lessons from England’s First Two Years of Mandatory BNG

Biodiversity net gain (BNG) has now been part of the mainstream planning process in England for more than two years. Since February 2024, major developments have been required to deliver at least a 10% uplift in biodiversity, using the statutory biodiversity metric and a clear mitigation hierarchy. The policy ambition was straightforward: leave nature better off than before. The delivery reality has been more complicated.

For developers, local authorities and land managers, the first two years have provided useful evidence. Some parts of the BNG market are beginning to mature. Habitat banks are emerging, metric calculations are becoming more familiar and planning authorities are building rudimentary systems for assessment. Yet significant operational risk remains, particularly around baseline data, long-term management, monitoring and enforcement.

What the first two years have shown

The early period has exposed a gap between policy design and delivery capacity. Developers understand the requirement in principle, but often underestimate the time needed to secure credible off-site units. Local planning authorities are managing BNG within stretched planning departments. Land managers see an opportunity in habitat banking, but face uncertainty over pricing, contracts and long-term obligations.

The result is a market that works in some places and stalls in others. Where authorities have clear validation processes and a pipeline of habitat schemes, BNG can be incorporated into development proposals with reasonable confidence. Where capacity is thin, negotiations become slower and more adversarial. That variability is itself a risk for developers operating across multiple planning authorities.

Habitat banking: supply is emerging, but not evenly

Habitat banks are central to the government’s vision for BNG. In practice, supply is uneven. Some land managers have registered schemes and are selling units. Others are waiting to see how prices settle before committing land and capital. The result is a fragmented market with limited transparency on price and availability.

For developers, this creates a procurement risk. A habitat bank may have the right broad habitat type but not the specific units needed for a scheme. Units may be available in principle but not yet secured through a conservation covenant or planning obligation. Due diligence therefore needs to go beyond a broker’s list. Developers should check the legal status of the site, the management plan, the monitoring arrangements and the evidence behind the unit calculation.

The risk is not that habitat banking fails. It is that developers treat it as a simple commodity purchase when it is a long-term environmental obligation with legal and reputational consequences.

Baseline and metric discipline

BNG depends on a credible baseline. If the pre-development habitat condition is overstated, the net gain calculation becomes unreliable. If it is understated, the development may appear to deliver more gain than it does. Either way, the metric can create a false sense of precision.

The first two years have shown that baseline surveys need proper ecological input, not a desk exercise. Local authorities should challenge weak evidence, but many lack the capacity to do so consistently. Developers should therefore treat the metric as a decision-support tool, not a compliance box. Early ecological advice is usually cheaper than late remediation.

Monitoring and long-term management

The 10% gain is not delivered when planning permission is granted. It is delivered over decades. That makes monitoring and long-term management the weak point in many BNG arrangements. Management plans can look robust at approval stage but fail in practice if responsibilities, funding and reporting are unclear.

Land managers need realistic budgets for habitat management, monitoring and contingency. Developers need assurance that off-site providers will still be able to deliver in ten or thirty years. Local authorities need a way to track obligations without creating an unmanageable administrative burden.

Conservation covenants and planning obligations provide legal mechanisms, but they do not manage habitats. People and funding do. The operational risk is that monitoring becomes a paper exercise, with annual reports submitted but not checked, and management failures identified only when habitats have already declined.

Viability and local authority capacity

BNG has a cost, and that cost interacts with viability. For some schemes, the need to secure off-site units can affect land value, affordable housing delivery or infrastructure contributions. Developers should model BNG early, not after the design has been fixed. Local authorities should be clear about what evidence they will accept and how they will treat residual risk.

Capacity remains the central constraint. Planning authorities are being asked to validate metric calculations, assess management plans, monitor obligations and enforce breaches. Many are doing so with limited ecological expertise. That creates inconsistency and delay. It also increases the risk that poorly evidenced schemes are approved while better ones are held up by process.

Enforcement and assurance gaps

Enforcement is the least mature part of the system. There is no simple national register that gives a complete picture of BNG obligations, and local authorities have different approaches to monitoring. The risk is not necessarily widespread non-compliance. It is the absence of consistent assurance.

For developers, this cuts both ways. A weak enforcement environment may feel permissive in the short term, but it creates uncertainty for those trying to do the right thing. If standards are inconsistent, responsible developers can be disadvantaged by competitors who submit weaker evidence. For land managers, weak assurance undermines confidence in the habitat bank market.

Where BNG is beginning to mature

There are signs of progress. More ecological consultants understand the metric. Some local authorities are developing standard validation checklists. Habitat banks are moving from concept to contracted supply. Developers with repeat experience are building BNG into land acquisition and master planning earlier.

The most mature approaches share three features: early ecological input, realistic long-term budgets and clear contractual allocation of risk. They treat BNG as an infrastructure requirement rather than a planning negotiation.

Practical implications for the next phase

Developers should stress-test their BNG assumptions, particularly where off-site units are critical to viability. Local authorities should focus on consistent validation and proportionate monitoring rather than adding new layers of process. Land managers should be honest about management costs and only promote schemes they can sustain.

Above all, the sector needs to recognise that BNG is a long-term delivery model. The first two years have shown that the policy can work, but only where the operational details are taken seriously. The next phase should be less about proving the concept and more about proving the delivery.