Architects in London

Which London council actually decides your application?

A postcode in London sits inside exactly one of 33 local planning authorities: the 32 borough councils plus the City of London Corporation. Each runs its own online planning search, validation checklist and committee. There is no single London portal, so the first job for any project is to confirm the borough. GOV.UK's find your local council tool does that from a postcode, and our guide to finding your local planning authority explains what to look for once you are on the council's site.

Two planning layers sit above the borough. The Mayor's London Plan sets strategic policy, including its policy on small housing sites under 0.25 hectares, which matters if your idea is closer to adding a home than adding a room (London Plan 2021, chapter 4). National permitted development rules then apply on top, except where a borough has switched them off locally. Everything else, from garden basements to window styles, comes from borough documents.

What do the London decision figures say?

Between July 2025 and June 2026 the 33 authorities together decided 23,967 householder applications. They granted 85.8% of them, and we calculate that 93.5% were decided within eight weeks or an agreed extension (MHCLG planning statistics). Those are London-wide sums. A single borough's approval rate can sit well above or below that average, so look up the council you will actually apply to, and treat the figures as context, not a forecast for your drawing.

How different can borough rules really be?

Quite different, and the councils say so in their own words. Islington reports that it has removed permitted development rights through an Article 4 direction in 40 of its 42 conservation areas, so even changing external doors or windows may need an application there (Islington, permitted development). Lambeth lists nine conservation areas with directions, among them Albert Square, Hyde Farm and Stockwell Park (Lambeth, Article 4 directions). Haringey's page describes four directions within conservation areas, alongside separate ones for houses in multiple occupation (Haringey, Article 4 directions).

Basements show the same pattern. The Royal Borough of Kensington and Chelsea adopted a Basements supplementary planning document on 14 April 2016 to support the basement policy in its 2019 Local Plan (RBKC, Basements SPD). Camden publishes its own basement guidance and asks for supporting technical assessments (Camden, basement developments). A neighbour two boroughs away may have nothing comparable. The lesson is to read your own borough's documents before you accept advice that was true somewhere else.

What does London's housing stock mean for a project?

Adding the two Council Tax age bands, roughly half of London's dwellings predate 1940: 28.9% were built before 1919 and 22.0% between 1919 and 1939 (VOA, Council Tax stock of properties 2026). The figure includes flats as well as houses. For a house of that age, an architect will usually start with what is already there: solid brick walls, shallow rear returns, ground-floor levels that differ from the garden and shared roof lines. Those features drive structure, daylight to neighbours and the visual case you make to the planners.

Terraces and semis also mean shared walls, which brings the Party Wall etc. Act 1996 into most London projects. The Government's booklet says notice for work to a party structure is due at least two months before the planned start, and one month for certain excavations near a neighbour's building (GOV.UK booklet). Our page on party wall matters covers the process; here the point is timing, because that notice period can sit on the critical path of a tight London programme.

Is it worth asking the council before you apply?

Many boroughs sell pre-application advice, and what you get varies. Richmond upon Thames, for example, runs a charged written service for householders with non-listed homes and says it does not include a meeting with an officer; a separate category covers listed buildings and includes a site visit (Richmond, pre-application advice). Another borough may offer a meeting, a free enquiry or nothing for small schemes. Ask whether the advice is written, who gives it and how it is recorded, because that shapes how far you can lean on it.

Which London projects do these pages cover?

• Extensions in London: rear and side additions in terraces, and the borough design guides that govern them.
• Loft conversions in London: roof volumes, conservation areas and shared roof lines.
• Planning applications in London: navigating 33 portals, validation lists and decisions.
• For the general rules behind these projects, see our national page on extensions.

How do you choose an architect for a London brief?

Start with the register. Anyone using the title architect in the UK must be on the ARB register, and you can look up a name or business address at architects-register.org.uk before you pay for anything. Then judge the shortlist on London-specific questions, using the checklist below.

• Which borough's planning team have they dealt with on a project like yours, and can they point to published decisions?
• How would they check conservation area and Article 4 status for your street?
• Do they expect a party wall surveyor, a structural engineer or a basement impact specialist, and who appoints them?
• Is the quote written, itemised by stage and based on the same brief you gave the others?
• What do they say if your idea looks unlikely to be supported, and how would they test it cheaply first?