Retrospective planning permission for a London house costs £1,173 at the starting point: from £475 drawings + £150 survey (£625 total) for the survey, drawings and planning case, and the council's £548 householder fee. Whether you pay it is a separate question, and this post covers that first.
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Building something that needed permission without applying is a mistake many owners make in good faith, often because a builder said it would be fine. A mistake can be put right, but the right fix depends on how long ago the work was finished and what the council would think of it today.
Does the law allow permission after the work is built?
Yes. Section 73A of the Town and Country Planning Act 1990 says the permission a council may grant "includes" permission for development carried out before the date of the application, and it covers work built without permission, work built under a time-limited permission and work that broke a condition (section 73A). The council may date it from when the work was carried out.
The test is the same as for any application: does the work fit the council's planning policies and the neighbourhood? Having built it first does not change that test, though the officer can stand in the street and see the work instead of picturing a drawing.
What does it cost, line by line?
Two bills, paid to two parties, and a third cost that people forget:
- Our fee, from £475 drawings + £150 survey (£625 total), covers the survey of the work as built, the drawings and the written case for it.
- The council's fee, £548 for a householder application (applications made on or after 1 April 2026, per the MHCLG fee table). The government's fee guidance describes doubling only for deemed applications and says the usual fee applies to retrospective ones (MHCLG guidance). If your case is for something other than a householder development, the fee is different, and we tell you which before you pay.
- Changes to the work. If the council grants permission with a condition, such as obscure glazing or a lowered roof line, the builder may have to alter what is there.
Is an application the only choice?
No, and sometimes it is the wrong one. Three routes sit side by side:
- Retrospective application. Right where the work is under ten years old, needed permission, and you think the council could accept it.
- Certificate of lawfulness. Right where the work is old enough to be immune from enforcement. In England the period is ten years from substantial completion for building work and ten years from the breach for most other breaches (section 171B). Section 115 of the 2023 Act brought that in on 25 April 2024 (section 115); older work is caught by the earlier four-year rules in some cases, which our lawful development certificate guide walks through.
- No application. Right where the work was permitted development all along. Check with the permitted development checker before you spend anything.
The certificate route is a different service with a different price, our certificate of lawfulness work, and it needs evidence of the date, not an argument about merits. We would rather tell you that on the phone than draw a retrospective application you do not need.
What decides whether the council will grant it?
The same things that decide any application. For a house in London they are usually:
- the size and height against the neighbours' windows and gardens;
- the materials and the character of the street, which count for more in a conservation area;
- whether the work breaks a condition attached to an earlier permission;
- any objection from neighbours, which the council must weigh.
Across London's councils, 20,556 of 23,967 householder decisions from July 2025 to June 2026 were granted (MHCLG live table PS2). That figure includes every kind of householder case, not only retrospective ones, so it describes how councils treat ordinary householders rather than your case. Work that has already upset a neighbour is judged on harder facts than the average.
What does the process look like?
We start with a short call about what was built, when, and what the council has said so far. If the council has already written to you, send us the letter. Then we survey the work as it stands, draw it and write the case.
The council has a statutory period to decide, and what happens in the meantime depends on its enforcement position. We are not a firm of solicitors, so if the council has served a notice, speak to a planning solicitor as well.
Frequently asked questions
Will the council fine me for applying after the event? The planning fee is the same £548 for a householder application, and nothing in the fee table adds a penalty for being late. Enforcement is a separate process the council may or may not pursue.
Can I get a refund if the application is refused? No. The fee pays for the decision, not the outcome. If the council refuses, you can appeal, and our householder appeal service is priced on its own.
My builder says he will sort it. Should I let him? Builders can submit applications, but the case has to be made in planning terms and the plans have to be accurate to what was built. A set of drawings from the survey of the finished work is what the officer relies on.
What if the work breaks building regulations as well? Planning permission and building regulations are separate approvals. Work built without approval can be put right through a regularisation certificate; see our regularisation cost post.
If the application goes through the Planning Portal, the Portal adds its own service charge: nothing, £99 or £149 including VAT, depending on the application type and complexity, paid to the Portal at submission and not normally refunded with a council fee (Ashford Borough Council, Planning Portal service charges, 11 September 2026). It is not ours and not the council's. Other submission routes exist; where your council accepts one without a charge, we can use it.
