What is permitted development, and what can you build without planning permission?
Permitted development is planning permission granted nationally by legislation rather than by your council. If a project stays inside every published limit — depth, height, materials, position — it needs no planning application. Exceed one limit, or sit under an Article 4 direction, and it does.
Permitted development in one paragraph
Permitted development is planning permission granted nationally by legislation rather than by your council. If a project stays inside every published limit — depth, height, materials, position — it needs no planning application. Exceed one limit, or sit under an Article 4 direction, and it does.
Legal basis: Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 1 (development within the curtilage of a dwellinghouse).
What the London numbers show
These are government figures for all 33 London boroughs, not estimates. They are the same numbers we publish on each borough page, summed — so if a borough page and this page ever disagreed, one of them would be wrong.
Larger householder extensions across London
Prior-approval outcomes for extensions beyond the ordinary limits, 2024 Q2 to 2026 Q1.
| Went ahead — prior approval not requiredNo neighbour objected, so no council decision was needed | 6,133 |
|---|---|
| Granted after assessment | 1,224 |
| Refused after assessment | 2,328 |
| Granted where a decision was neededOnce a neighbour objects, refusal is the more likely outcome in London | 34% |
Source: Ministry of Housing, Communities and Local Government (PS1 district planning application statistics). Open Government Licence v3.0 Extracted 2026-08-16.
Certificates of lawful development across London
Certificates decided by the 33 London boroughs, 2024 Q2 to 2026 Q1.
| Certificates decided | 23,851 |
|---|
Source: Ministry of Housing, Communities and Local Government (PS1 district planning application statistics). Open Government Licence v3.0 Extracted 2026-08-16.
The limits that actually catch London homes
The rules are dimensional and unforgiving, and they are read strictly. A single-storey rear extension on a terraced or semi-detached house may project three metres from the original rear wall, four metres on a detached house, with a maximum height of four metres and eaves no higher than three metres within two metres of a boundary. A loft conversion is limited to forty cubic metres of added volume on a terrace and fifty on a semi or detached house, must not extend beyond the plane of the existing roof slope on the principal elevation, and must not sit above the highest part of the existing roof.
Two words in that paragraph do most of the damage. "Original" means as the house stood on 1 July 1948 or when it was built, not as you bought it — a 1970s addition you never saw has already spent part of your allowance. And "dwellinghouse" excludes flats and maisonettes entirely: a flat has no permitted development rights for extensions at all.
Where permitted development simply does not apply
Flats and maisonettes, listed buildings, and anything where a planning condition on the original consent removed the rights — common on estates built since the 1980s. In a conservation area, side extensions and roof extensions lose their permitted development status even without an Article 4 direction, and cladding is excluded.
The larger-extension prior approval route
A rear extension of up to six metres on an attached house or eight on a detached one is possible under the neighbour consultation scheme, but it is not automatic: you notify the council, neighbours are consulted, and if any object the council decides whether the impact on amenity is acceptable. Across London the refusal rate on that route is high enough that it should never be assumed.
If it is permitted development, why would I apply for anything?
Because permitted development is a legal status, not a document. Nobody has checked your project against the limits, and nothing records that it complied. That becomes a problem at exactly the wrong moment: a buyer's solicitor asks for evidence, and the absence of any is a defect that delays or reprices a sale.
A lawful development certificate fixes that. It is a formal determination that the works are lawful, decided on facts and dimensions rather than on taste, and it is the reason London councils decide tens of thousands of them a year.
Permitted development does not exempt you from building regulations
These are two separate regimes and satisfying one says nothing about the other. Planning asks whether the building may exist in that form. Building regulations ask whether it is safe to occupy: structure, fire escape, insulation, ventilation, drainage. Nearly every extension and loft conversion needs building regulations approval regardless of its planning route, and a loft conversion has escape and fire-separation requirements that routinely change the design.
Permitted development: common questions
How do I prove my extension was permitted development?+
Do permitted development rights apply to flats?+
Does a previous extension use up my rights?+
Where permitted development affects the drawings
Sources
Not sure how permitted development applies to your property?
Send us the address and what you want to build. We will tell you which route applies before you spend anything on drawings.