Brownfield land: what is it, and why does it matter for planning?
The decision to build on a brownfield site can have a big impact on development timelines, budget, and building constraints. The terminology around planning policy can also be confusing. Understanding what brownfield land is, and how and where to find it, means you can identify opportunities that are more likely to pass through planning with relative ease.
In essence, brownfield land (also called a brownfield site) is land that has been built on before, in contrast with greenfield land, which has not. Contrary to what you might assume, not every previously built-on site counts as brownfield, and brownfield sites can be found in both urban and rural areas.
What is brownfield land? Definition and exceptions
The National Planning Policy Framework (NPPF) defines brownfield as "previously developed land," meaning land which is or was occupied by a permanent structure. There are, however, some notable exceptions. The following do not count as brownfield under the NPPF definition, even if they've been used or altered by people:
- Land used for agriculture or forestry
- Land that has been used for mineral extraction or waste disposal, where provision for restoration has been made
- Private residential gardens
- Land in built-up areas such as parks, recreation grounds, and allotments
A notable inclusion on this list of exceptions is garden ground, which is no longer seen as being “previously developed”. Moreover, where previous structures have blended back into the landscape, the site may no longer be seen as brownfield.
What counts as brownfield land?
In urban areas, this may include redundant land which was once used for employment and industry, such as abandoned warehousing or offices. These underused urban sites may offer ideal opportunities for smaller housing developments. An example (illustrated below) is this brownfield site in Wandsworth, where a planning application previously sought to demolish existing buildings, including an MOT garage, to create eleven flats with associated landscaping.
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This is where Searchland’s planning tool comes into its own, with access to in-depth, historical information on local authority decisions, to help save time and inform your strategy.
Larger urban sites, such as the conversion of the former gasholder site in London's King's Cross, also demonstrably support redevelopment including associated commercial builds and amenity infrastructure.
Contrary to perception, brownfield land can also be found outside of cities and towns – including within the Green Belt – opening up the possibility of future development in these highly restricted areas.
Planning policy and brownfield land: what developers need to know
The NPPF was substantially revised on 17 August 2026, replacing the December 2024 version. The current framework separates policy for plan-making from policy for decision-making, and it continues to give strong support to reusing brownfield and underused land. In practice, that support now looks like this:
- A stronger presumption for previously developed land. Under decision-making policy S5, redevelopment of previously developed or brownfield land (including a change of use) now benefits from a default-in-favour "tilted balance" outside settlement boundaries, a broader form of support than the previous wording.
- A tighter Green Belt bypass. Policy GB8 restricts the mechanism developers have used to flex requirements (such as affordable housing percentages) on brownfield Green Belt sites: they must now show the land is "demonstrably burdened" by unexpected costs left over from its previous use.
- The Vacant Building Credit is back. Policy HO8(4) reinstates a reduced affordable housing contribution, proportionate to the amount of existing vacant floorspace a scheme reuses.
If you're assessing a site's viability under the new framework, it's worth having a planning consultant confirm how these specific policies apply, since the practical effect will vary by local plan status and site history.
What is the Brownfield Land Register?
Since 2017, local planning authorities in England have been required (under the Town and Country Planning (Brownfield Land Register) Regulations 2017) to prepare, maintain, and publish a public register of brownfield sites, reviewed at least once a year.
To qualify for the register, a site generally needs to:
- Be at least 0.25 hectares, or capable of supporting at least 5 dwellings
- Be suitable for residential development
- Be free of legal constraints that would prevent housing being delivered
- Be deliverable within 15 years
The purpose of this Government-led scheme is to help house-builders to more easily identify sites that are suitable for development. Included in the register are details of site name, co-ordinates, ownership, physical size, planning status and an estimated number of dwellings (Source: Planning Portal, 2022).
Does being on the Brownfield Register mean a site has planning permission?
Not quite. The Brownfield Land Register sets out details of all potentially suitable sites that meet the definition of “previously developed land”, irrespective of planning status. However, “Part 2” of the list includes those sites that have been granted “permission in principle” for residential development, as satisfying the principles of use, location and number of units (after meeting consultation requirements).
Interested parties will still need to submit planning applications for these sites, including technical details of the build, however, the net result will be to both create more certainty and shorten the time needed for each submission.
What can you build on brownfield land?
Brownfield sites aren't limited to housing. Commercial schemes and renewable energy projects are increasingly directed toward brownfield and previously developed land too. For solar farms specifically, planning guidance encourages developers to use previously developed and non-agricultural land where possible, though it stops short of ruling out agricultural sites.
Challenges of developing brownfield sites
Brownfield land often looks like the perfect fix for the crunch on space, especially in crowded cities. But, it's not always smooth sailing - the land itself can present particular challenges that developers, planners, and stakeholders need to keep an eye on:
Road access: Brownfield land can often be located in areas with limited vehicular access or road networks unsuitable to support heavy plant traffic.
Ecology and habitats: Land that has gone unused for generations may now be home to protected species not found anywhere else - which could prevent development especially if it disturbs the ecology of the site.
Heritage: Some sites may be part of the local heritage of the area or include structures or geographical features with historical significance.
Contamination: Before you start building on brownfield land, especially if it was once used for industrial purposes, you have to tackle any existing contamination like asbestos, lead, fuel and chemicals.
Air quality: If the land was previously used for commercial or industrial activities, it's important to consider the air quality of those who will be using the space.
How Searchland helps developers source brownfield opportunities
Searchland brings Brownfield Land Register data together in one place, standardised across local authorities, so you can filter by size, ownership, planning status, and application history instead of checking each council's register individually. Combined with our wider planning and ownership data, it's a faster way to build a shortlist of viable Brownfield opportunities.
Have a look at the example below; this shows sites listed on the Brownfield Land Register in and around the Greater London area. You can filter by size, drill down to find details of land ownership, and planning status and view details of the planning applications.
Furthermore, our strategic mapping system lets you include land ownership, boundaries and planning constraints, saving you time and resources in filtering and finding the most viable possibilities.
Why brownfield land should be part of your development strategy
The term brownfield is often used within planning descriptions, however there are ambiguities in interpretation which may cause stumbling blocks in the planning process. From a policy perspective, the most important distinction is that brownfield sites are much more likely to achieve planning permission (and indeed may have “permission in principle”).
Searchland can help you weed through prospective sites and source opportunities to suit your planning pipeline - book a demo with us today!
