How can developers meet the new Biodiversity Net Gain requirements?

A recent Planning roundtable, in association with Shoosmiths, shared best practice advice on how to meet the government’s requirement for new developments to deliver a biodiversity net gain of ten per cent from 2023.

Planning professionals sitting around a table.

The Environment Act 2021 is going to be a game-changer when it comes to new developments: from November 2023, any new development must deliver a net gain in biodiversity (BNG) of 10 per cent, either onsite or by offsetting. But there are fears over its implementation: how can local government or planning officers ensure genuine gains are made? How will it be resourced and what are the business benefits? How will it affect developers?

To tackle these issues, Planning brought together a roundtable of industry experts, in partnership with major law firm, Shoosmiths, to look at the gist of the proposals and how everyone from government to developers should be looking to implement them.

Implementing the biodiversity requirements

The driver of the change is of course the government and it is they who in the first instance will be responsible not just for setting out specific requirements, but making sure that they are workable throughout the industry. Emily Cole is biodiversity net gain policy and legislation advisor at the Department for Environment, Food and Rural Affairs (DEFRA). “The requirement is going to be implemented in stages,” she says. “The intention is that it is not an add-on at the end point of a building project, but something that is integral to the project, from the moment of site selection, including understanding site value and engaging with the local authority.”

The government is well aware of the issues involved: costs, an understandable desire to minimise risk, as well as monitoring and evaluation, while providing guidance to check that the project has been successfully implemented. There is also an appreciation that further changes have the potential to impact the viability of development pipelines so any major changes in the metric are anticipated to only be introduced every three to five years.

Developers must follow government policy

But it is the developers themselves, not the government, who will be working to comply with policies and legislation when the act comes into force. So how will developers respond? “It’s already on the radar and developers have been looking for ways to respond,” says Lisa Tye, a partner at Shoosmiths. “Developers are always looking for clarity. Most of the work I do currently involves delivering off-site solutions, but onsite BNG (if there is scope for it to be provided) tends to be easier to deliver. A challenge for residential developments, however, is that they are often quite constrained in terms of appropriate space in which to incorporate biodiversity.”

There are also other issues for developers: for example, there is a view that the cost of implementing BNG solutions should cover monitoring costs, with long term monitoring essential to ensuring biodiversity requirements are constantly being met. There is also the debate around what to do if BNG is not being maintained in the right way, as could happen in, say, a residential development that will be in use for decades. Would there be a penalty? How would it be levied? Cole went on to reveal that DEFRA is working with Natural England to look at some of these wider issues, emphasising the need for consistency across the board.

Emily Cole: "The intention is that it [BNG] is not an add-on at the end point of a building project, but something that is integral to the project, from the moment of site selection, including understanding site value and engaging with the local authority.”

“Developers have different levels of understanding on BNG,” says Lucy Greenwood, director, Savills. “Some are less aware whereas others are quite advanced in their understanding. Those planning strategic sites are working out if they can provide all the BNG onsite in the future and discovering the starting state of the land makes a big difference. For example, a site which is grass fields with hedges can have a high level of biodiversity, but one with agricultural crops has a very low level of biodiversity. There are still many unknowns about how the policy will work, so clarity over the details is required to fully understand what is needed for different sites.”

Impact on nearby habitats

“Developments can also disrupt the habitats of wildlife offsite as well as onsite, for example due to the displacement of air or water pollution,” Tye goes on to say. “Developers will need to work closely with planners to consider and minimise the wider impact of their developments and the knock-on effect in nearby areas. Building biodiversity into a scheme retrospectively to compensate can be difficult and cause delays, so developers need to be screening for the potential impact of their works on nearby habitats well before submitting a planning application.”

There is also the issue of whether to provide BNG on or offsite. “We are pro BNG anywhere,” says Alexa Culver, general counsel, Environment Bank. ”Onsite is beautiful and brilliant for people – but not necessarily for nature. Nature needs to move around in bigger, better, joined up sites – we talk about ‘nature for people’ and ‘nature for nature’ - both are important. We deliver nature for nature.”

She supports the use of habitat banks, which enable smaller developments with offsite needs as well as the bigger ones.

More measures needed

But that is not all. “BNG alone can’t provide all the nature recovery required – we need more measures in place that work effectively together,” says Rebecca Moberly, principal consultant – environment, Planning Advisory Service. “We should take a wider look at land use, not just development.”

And there is the issue of BNG having a positive impact on social value. “Social value is provided through access to nature,” says Tye. “Designing biodiversity into developments from the start is a way of ensuring they are future-proofed and capable of promoting a sense of community and supporting the wellbeing of residents."

And of course, such considerations will continue to feature in the minds of the residents of these developments long into the future – having an ongoing impact on the developer’s bottom line.

With just over a year to go, developers and local authorities will need to get to grips with the requirements and factor the costs and measures into their development plans. Otherwise, we could see a hike in the number of schemes deemed not to be BNG compliant being sent straight back to the drawing board.

For further advice on meeting BNG requirements, email Shoosmiths at or

This article was edited in consultation with the sponsor, Shoosmiths

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