With mandatory Biodiversity Net Gain (BNG) now a core requirement of the planning system in England, developers are expected to ensure that new projects measurably enhance rather than diminish biodiversity. But what happens if these targets aren’t met?
Understanding the real-world legal and financial risks is essential for those involved in planning, development, or land management.
Biodiversity Net Gain: What’s Required?
Under the Environment Act 2021, most developments in England must deliver at least a 10% biodiversity gain compared to the site’s baseline habitat value. This uplift, calculated using the statutory Defra Biodiversity Metric, must be demonstrated as part of a Biodiversity Gain Plan and submitted before development begins. Gains can be achieved on-site, off-site, or, if necessary, via statutory biodiversity credits as a last resort.
The overarching goal is not just to halt biodiversity loss but to actively improve ecological quality and connectivity across England’s landscapes.
Planning and Legal Consequences of Falling Short
Non-compliance with BNG requirements has real implications. If a Biodiversity Gain Plan is missing, incomplete, or cannot credibly demonstrate how the 10% uplift will be delivered, planning permission can be delayed or refused. BNG is secured through legally binding mechanisms such as planning obligations (Section 106 agreements) or conservation covenants. These agreements often extend for 30 years or more, with enforcement powers resting with local authorities or designated responsible bodies.
Where agreed habitat enhancements are not delivered due to inadequate management, flawed ecological data, or changes in land use, developers may face enforcement action, project disruption, or reputational risk. This highlights the importance of building robust, realistic delivery mechanisms from the start.
Early Engagement and Expert Support are Key
Successfully delivering Biodiversity Net Gain (BNG) requires upfront ecological planning and clear pathways for habitat creation, management, and monitoring. Professional ecologists provide critical support in assessing baseline biodiversity, interpreting the Biodiversity Metric, and designing interventions that align with both planning policy and site-specific constraints.
Engaging a consultant ecologist early also helps reduce the risk of unexpected costs. Early metric calculations can flag potential shortfalls in on-site delivery, allowing developers to explore cost-offsetting solutions well in advance. Speaking to an offset provider early in the process provides a clearer picture of potential unit costs—helping avoid financial surprises later.
Where on-site solutions are limited, purchasing biodiversity units from a reputable provider can offer a streamlined alternative. It shifts the responsibility for long-term delivery and monitoring to a specialist, simplifies project timelines, and provides cost certainty with one-off pricing rather than ongoing financial commitments.
Equally important is involving oversight bodies and habitat managers from the outset to secure long-term delivery, whether on-site or via trusted off-site solutions.
A Risk Worth Managing And an Opportunity Worth Seizing
Biodiversity Net Gain is more than a compliance requirement; it’s a catalyst for restoring nature through development. But the risks of getting it wrong, legal, financial, and reputational, are real. With early planning, trusted ecological input, and access to reliable off-site habitat providers, these risks can be managed and transformed into long-term benefits.
Civity works across the public and private sectors to help clients meet their BNG obligations with confidence, whether that’s through helping to prepare compliant Biodiversity Gain Plans, brokering off-site units from our landbank, or coordinating with local planning authorities. We bring deep ecological expertise and planning insight to ensure BNG delivery is not just achievable but meaningful and enduring.
