Home building delays: Industry calls for reforms to Biodiversity Net Gain

Homebuilding industry raises issues with Biodiversity Net Gain

Two years on from the introduction of Biodiversity Net Gain (BNG) in England, a new survey has revealed the impact on the home building industry. The research, which was undertaken by the Home Builders Federation (HBF), finds that the delivery of new homes is being slowed, with the industry facing difficulties implementing current rules.

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What is Biodiversity Net Gain?

Biodiversity net gain (BNG) requires developers in England to deliver a measurable 10% positive impact on the biodiversity associated with their sites. It came into force for almost all developments in February 2024, and for smaller developments from April that same year.

“Biodiversity net gain is a way of creating and improving natural habitats. BNG makes sure development has a measurably positive impact (‘net gain’) on biodiversity, compared to what was there before development.”[i] – Department for Environment, Food & Rural Affairs (DEFRA).

The latest survey of 92 HBF members[ii], which was conducted in early 2026, found that BNG has influenced almost two-thirds (60%) of respondents in their decision not to pursue sites that may previously have been viable. A major cause for concern was the uncertainty around agreeing on the cost and type of biodiversity enhancements needed on a site.

Further, the expertise and capabilities of local authorities remains a notable bottleneck, with delays in reviewing biodiversity assessments continuing to affect a large proportion of home builders. 80% of survey respondents say that they have faced planning setbacks as a result of BNG regulation, with delays in reviewing biodiversity assessments affecting a large segment of the industry. Similarly, 66% cited insufficient resources or expertise, compared with 79% in a previous edition of the survey conducted in 2025.

Respondents went on to say that they have reduced the number of homes on a site in response to these pressures, as land must be set aside for habitat creation and enhancement, which raises concerns about overall site viability. In addition, the industry is facing a huge increase in taxes and policy costs generally; including a further Government levy of £3k per home coming into play this Autumn, alongside the recently announced Future Homes Standard which is estimated to cost on average £10k per home. It means that flexibility in a development's finances has been severely curtailed.

Industry calls for reforms

Two years after its introduction, the UK government is currently consulting on reforms to BNG, including the possible introduction of a 0.2 hectare (ha) area-based exemption, meaning sites smaller than this threshold would not be required to deliver BNG. Local authorities will also be restricted in setting their own BNG requirements on most sites.

However, industry response has been cautious, with only a third of SME home builders believing that the changes will improve the cost and ease of delivering BNG, while 63% do not expect the measures to make a substantial difference, according to HBF’s survey.

As a result, HBF has urged the government to ensure BNG is implemented without restricting housing supply by addressing the recruitment crisis for public sector ecologists, providing clearer guidance, and including baseline biodiversity assessments in local plans. It also stresses the need for further consideration of cumulative policy cost pressures and calls for Government to scrap incoming financial burdens on development, such as the Building Safety Levy and rising Landfill Tax, rather than reconsidering BNG in its entirety. The report also suggests stronger support for SMEs through a higher threshold for ‘smaller sites’, as the proposed exemption of 0.2 hectares is widely seen as too low, a more accessible off-site biodiversity market, and a Quality Mark for units.

Neil Jefferson, Chief Executive at the Home Builders Federation, has commented: “The cumulative impact of Biodiversity Net Gain requirements and wider cost pressures is increasingly affecting the viability of housing developments, with too many sites becoming difficult to bring forward.”[iii]

He stresses that while the home building industry supports the goals of BNG, as well as remaining committed to delivering new homes and meaningful improvements to nature, it needs the government “to provide greater clarity and ensure a consistent approach across local authorities and to provide support for SME builders so that these requirements do not become a barrier to delivering much-needed housing.”[iv]