The Act requires that habitat creation or enhancement is calculated using Biodiversity Metric 3.1 and can be delivered on-site, off-site or via statutory biodiversity credits. Before the commencement of new development, the existing and proposed biodiversity values of the site must be quantified and plans put in place to exceed the biodiversity level.
In advance of Autumn 2023, Local Plans are already implementing a requirement for BNG, as research by Carter Jonas among all English 322 planning authorities has found. The research collected data in December 2021 on planning policies which expressly set a requirement for measurable net gain using a recognised metric.
Adoption of BNG
As the Local Plan process spans several years, the number of local planning authorities (LPAs) that have implemented such policies is low. Only 5% have an adopted BNG policy and 23% have emerging policies, which are likely to be afforded greater weight in the decision-making process as they near adoption.
However, the relative proactivity of some regions indicates where BNG has progressed in policy to a greater extent, and where developers and landowners should refine their strategies. The West Midlands has made substantial progress, with 53% LPAs having BNG policy either adopted in Local Plans or emerging and South East is also ahead, at 32%.
In the East Midlands, 88% of LPAs have neither a formal policy in place nor a policy emerging, and although a small number have policies in discussion, every LPA in London and the North East is yet to have adopted a BNG policy.
The policies of ten LPAs exceed the 10% minimum. Six of these are in the South East, two in the South West and one each in both the North West and East.
The impact of planning decisions
Research shows a correlation between a high number of major planning decisions and progresses towards BNG: while 42% of LPAs that made 70 or more major planning decisions in the year to September 2021 have an adopted or emerging BNG policy in their Local Plan, this compares to only 22% of those that made 0-39 major planning decisions.
Land uses and the importance of non-developed land
According to Government data, 91.5% of land in England is not developed, although this varies significantly between regions. Looking at the composition of land indicates where challenges and opportunities lie for developers and landowners.
Major developments will put the supply of undeveloped land available for off-site BNG in high demand. Interestingly, the average number of major planning decisions was marginally lower in urban local authorities last year than in rural areas, at 34 and 42 respectively. Predominantly urban areas, which have lower levels of undeveloped land, have a lower risk of habitat loss and so lower BNG requirements. However, this is balanced by limited opportunities to provide BNG on-site.
Selecting land for off-site solutions will be guided by the land’s geographic proximity to the development site as the ‘spatial risk’ multiplier within Biodiversity Metric 3.1 results in off-setting on land within closer proximity being awarded a higher score. But offsetting far from the development site is sometimes unavoidable, even if (because of the spatial risk multiplier) it results in developers having to deliver BNG over a larger land area or to a higher level.
Agricultural land, which accounts for 68% of rural landmass (but only 28% in rural LPAs), is best placed to accommodate off-site BNG as arable land can be repurposed as woodland or heathland. Accordingly, there is a lack of suitable land in urban LPAs. For example in Birmingham, residential gardens account for over 28% of the total land use and almost half of the undeveloped land; only 6.33% of Birmingham’s land is agricultural and 3.18% is forestry or woodland, providing few opportunities for off-setting.
Off-site BNG, however, can be more beneficial as a high proportion of on-site green space reduces density, adversely impacting development value.
Conclusion
The balance of offsite/onsite and the location of land for BNG credits is a nuanced one, varying considerably across locations. With the only unquestionable impact being a rise in land values across most regions, it is vital that developers give the matter early consideration.
