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New planning laws force builders to boost nature rather than destroy it

New planning rules aim to leave the natural environment in a measurably better state after a building project than it was before. The scheme, known as Biodiversity Net Gain (BNG), became mandatory in England from February 2024. Under the new law, developers not only have to protect wildlife and natural habitat but boost biodiversity by 10 per cent to gain planning permission. The new rules will see developers required to take steps such as creating new woodland and ponds or restoring natural wetland, where possible within the project itself.

Why is it important?

The UK’s wildlife is under threat and urgent measures are needed to protect and restore it. Britain is one of the most nature-depleted developed countries in the world, having lost nearly half of its biodiversity since the industrial revolution.

According to government watchdog, the Office for Environmental Protection, wildlife has been declining at an “eye-watering rate.” Since the 1970s, 41% of UK species have declined and 26% of  mammals are threatened with extinction, reveals the State of Nature report. Amphibians and reptiles are also at risk with 31% facing an uncertain future while insect species have reduced by 18% over the last 50 years. Intensive farming and urban spread triggered by the agricultural and industrial revolutions are often cited as major factors causing this nature loss.  

What has changed?

BNG forms part of the government plans to halt the decline of species and habitats, including wildflower meadows. Before the new rules were introduced, local authorities could set their own targets and seek “no net loss” of wildlife or natural habitat. The new law will enforce a net gain of 10 per cent if developments are to get permission. The new legislation will require planning applicants to produce a ‘Biodiversity Gain Plan” to show how much biodiversity is on the site before and after development. Developers will have to commission surveys by ecologists and agree measures to ensure there is improvement.

If it’s not possible to make a site more biodiverse, for example a new city centre office block, there will be an offsetting scheme where developers can buy “credits” to pay government or landowners to improve habitat elsewhere. This involves putting a financial value on plants, animals and habitat. That action could help offset the loss, though it’s supposed to be a last resort.

The new biodiversity rules became law under the Town and Country Planning Act, making biodiversity gain a condition of planning permission. Similar biodiversity rules are to be introduced for Scotland, Wales and Northern Ireland.

Has BNG been welcomed?

Conservation charities say the legislation is long overdue. BNG could help declining species ranging from hazel dormice to bees as well as increase people’s access to green space or water. “All new development should aim to be biodiverse and create green infrastructure, such as pollinator-rich gardens, native trees and new hedgerows,” said Rachel Hackett, living landscape development manager at the Wildlife Trust. “If done well BNG will offer a positive step forward in the way we think about nature and development in a more integrated way. But adding just 10% in a time of nature crisis is not enough. We want to see developers go beyond the minimum and aim for at least a 20% gain for nature, with every single infrastructure having a positive impact for more wildlife.”

The response from home builders has been mixed. Bellway, which had a revenue of £3bn in 2021, called for the 10% biodiversity net gain to be “optional” during consultation and suggested a cost cap of £20,000 to £25,000 per dwelling. But Barratt Homes, the UK’s largest housebuilder, took the initiative and committed itself to a biodiversity net gain of at least 10% on all its designs submitted for planning a a year early.

BNG laws were originally meant to be introduced in November 2023 but were delayed until February 2024. This decision came after local councils voiced concerns over having sufficient resources to run the new scheme. More than 60% of public sector planning departments were unsure about their ability to secure the required resources and expertise to implement the new rules, according to a survey conducted by the Royal Town Planning Institute (RTPI).

Will BNG make a difference?

Conservationists say the measures – if implemented properly – could help declining species and habitats. While it welcomed the new rules, the Wildlife and Countryside Link (WCL), a coalition of nature organisations, argues councils need to aim much higher to restore nature, but few are planning to do so. Based on data collected from 317 local authorities in England under Freedom of Information requests, just 26 councils (8%) have either committed to or are considering setting requirements above the mandatory 10%. They include London’s Tower Hamlets and Kingston Upon Thames where 30% is proposed while Birmingham, Wiltshire and Devon were either planning or consulting on 20% uplift.

Meanwhile, an Environment Department (Defra) spokesman said they were working closely with local authorities and had provided over £25m to support implementation of the new rules. “We estimate that introducing a mandatory 10% gain will create areas of habitat the size of Bromley each year while striking the right balance for developers and positive outcomes for nature.”

What does it mean for home extensions?

House builders will need to show how they can improve flora and fauna compared to the pre-development state or else be forced into purchasing biodiversity credits. The biodiversity rules are mandatory for nearly all new build developments, including small schemes of nine homes or less. But individual householder applications, such as home extensions and loft conversions, are exempt from BNG rules, according to the government’s Planning Portal. However, local authorities are still required to consider the conservation of biodiversity when deciding a planning application under the National Planning Policy Framework, so it may still be advisable to comply.

Winchester City Council, for instance, publishes a ‘Biodiversity Checklist for Householder Applications’ to help work out if a building project is likely to affect natural habitats, protected sites or species. If a scheme is likely to impact biodiversity, additional information is required to support a planning application. For example, if a building project is within 50m of a designated Site of Special Scientific Interest (SSSI) or Site of Importance for Nature Conservation (SINC) or broad-leaved woodland, old/large trees, rivers, ponds, wetland marshes, flower rich meadows, water meadows or mature hedgerows, your proposal could affect biodiversity, according to the checklist. Similarly, if the works involves buildings with a known bat use or a mature/overgrown garden over 0.25 hectare it could be detrimental to nature.

If a home extension or loft conversion is likely to impact protected species or sites or habitats, then you will need to submit a biodiversity statement or other suitable report by an ecologist which demonstrates how harm will be avoided, reduced or mitigated. Plus, any proposals for enhancements of biodiversity. In some cases, specific surveys may be required, for example bat surveys. It’s always a good idea to check with your local authority the information required. If you have hired an architect, they can also advise you.