Brownfield land, made buildable.

The settlement policy says development should be approved unless the benefits are substantially outweighed by any adverse effects. The land policy names the places it means: space above shops; under-used retail and business sites; and service yards, lock-ups, car parks and transport infrastructure no longer required. Outside a settlement the redevelopment of previously developed land is one of the listed forms that can still be approved. The weight settles nothing else. Flood risk, ecology, heritage, access, design and viability all stay live; a site that fails one of them fails on that ground, not on its brownfield status. Where the land is also protected for employment use, the release test is a different question again, set out in the guide to loss of employment land.

The duty comes from the Town and Country Planning (Brownfield Land Register) Regulations 2017, which required registers by the end of that year. Part 1 holds every site the authority finds suitable for housing, with or without a permission. Part 2 is a subset of Part 1: the sites the authority has decided should carry permission in principle. The usual threshold for entry is a site of at least a quarter of a hectare, or one capable of taking at least five dwellings, though smaller sites can be entered. Absence from a register proves nothing: entry is the authority's decision and coverage is patchy.

It arrives by one of two routes, on application or by the authority entering a site in Part 2 of its brownfield land register. On application it is decided in five weeks and lasts three years by default; through a register it lasts five. Technical details consent then follows, with ten weeks for major development and five for anything else. The route is deliberately narrow. It is closed altogether to development needing environmental impact assessment, to habitats development, to householder work and to minerals; the application route is also closed to major development, which means ten homes or more, a thousand square metres or more of floor space, or a site of a hectare or more. On heavily constrained land the principle cannot be separated from the detail, so a full or outline application stays the realistic route.

A separate regime stands behind that one. Part IIA of the Environmental Protection Act 1990 lets a local authority identify land as contaminated where significant harm or significant pollution of controlled waters is being caused, or where there is a significant possibility of either. Liability falls first on whoever caused or knowingly permitted the substances to be there; where nobody can be found it can reach the current owner or occupier. Planning does not run that regime, but it sets a floor against it. The working standard is suitability for the intended use, so housing and a warehouse can need different things of the same ground. What to ask for before the money moves is set out in the guide to buying land.

The statutory objective is at least a ten per cent increase in biodiversity value. A biodiversity gain plan has to be approved before development may lawfully begin; the authority has eight weeks to decide one unless a longer period is agreed. Exemptions changed on 6 August 2026: for applications made from that date a site of 0.2 hectares or less inside the red line is exempt, but that exemption falls away if priority habitat on the site would be harmed. Open mosaic habitat on previously developed land is itself a priority habitat, exactly what a long-vacant yard grows. So the small-site exemption is least reliable on the sites that look emptiest. There is more in the net gain guide.

The other triggers are land the Environment Agency lists for critical drainage problems; and land a strategic flood risk assessment or the Flood Map for Planning shows to be at risk of flooding from any source, now or in the future. The sequential test is a separate question and it applies however developed the land already is. It asks whether reasonably available sites exist at lower flood risk within an area no larger than the catchment the development serves. Where they do, permission can be refused on that ground. In Flood Zones 2 and 3 some uses are refused outright and others face an exception test too. Neither being previously developed nor a housing shortfall exempts a site: guidance says a missing five-year housing land supply is not relevant to the test, though housing still weighs in the wider balance. Why a site fails in principle is covered in the guide to why development sites fail.

Guidance gives the arithmetic: a building of eight thousand square metres demolished as part of a ten thousand square metre scheme leaves a contribution of a fifth of what would otherwise be sought. It does not apply to a building that has been abandoned, nor, since August 2026, to major development in or released from the Green Belt. Abandonment is judged on the condition of the property, how long it stood unused, any use in between and what the owner intended. Authorities also look at whether a building was emptied to claim the credit. On the right conversion this does more for the numbers than any move we can make on a drawing.