Retrospective Planning Permission: What Happens Next

First, check whether you actually need one

• Three questions decide it, in order. Did the work need planning permission at all, or was it permitted development? If it needed permission, is it now immune from enforcement because of the time that has passed? Only if the answer to both is no does a retrospective application become the right move.

• In England, no enforcement action may be taken over unauthorised building work after ten years beginning with the date the operations were substantially completed. (legislation.gov.uk, September 2026)

• An unauthorised change of use to a single dwellinghouse is immune after ten years in England and four years in Wales, and every other breach of planning control carries a ten-year period running from the date of the breach. (legislation.gov.uk, September 2026)

• Where the work is already immune, apply for a certificate of lawfulness of existing use or development under section 191 instead. Uses and operations are lawful if no enforcement action may then be taken against them. (legislation.gov.uk, September 2026)

What the council can actually do

• Councils in England issued 1,435 enforcement notices in the quarter ending March 2026, against 68,400 planning decisions in the same quarter. Formal enforcement is the exception, not the norm. (MHCLG, June 2026)

• They also served 1,411 planning contravention notices in that quarter. A contravention notice is a request for information and is usually the first contact a homeowner receives, not a demand to demolish. (MHCLG, June 2026)

• Stop notices and temporary stop notices, which halt work immediately, were used 18 and 73 times nationally in the quarter. (MHCLG, June 2026)

• Enforcement is also discretionary. A council must consider whether action is expedient, which means minor breaches that cause no real harm often attract no action at all. That is not a reason to ignore a notice, but it is a reason not to panic at the first letter.

How a retrospective application is decided

• It is assessed on planning merit exactly as a prior application would be. The fact that the work already exists is not itself a reason for refusal, and the council cannot charge a penalty fee for lateness.

• A householder application costs £548 from 1 April 2026, the same whether it is made before or after the work. (Planning Portal, April 2026)

• Authorities granted 90% of householder applications in the year ending March 2026, so the base rate for domestic work is high, though a scheme built without the design compromises an officer would have asked for is a weaker case than one designed to be approved. (MHCLG, June 2026)

If it is refused

• Refusal of a retrospective application does not automatically mean demolition. The council must still decide whether to take enforcement action, and it must serve an enforcement notice to require anything to be undone, which carries its own right of appeal.

• 31% of Section 78 planning appeals were allowed in the quarter April to June 2026, so roughly two in three appeals against refusal fail. (Planning Inspectorate, July 2026)

• Enforcement appeals are slow: those decided in June 2026 took a median of 63 weeks, against 19 weeks for appeals generally. (Planning Inspectorate, July 2026)

Common questions

Can the council make me demolish an extension built without permission?

Only by serving an enforcement notice, and only if the work is not yet immune from enforcement. In England that immunity arrives ten years after the building work was substantially completed. An enforcement notice also carries a right of appeal.

Is retrospective planning permission more likely to be refused?

It is judged on the same planning merits as any other application, and lateness is not a ground for refusal. In practice the weaker cases are schemes built without the design changes an officer would have negotiated beforehand.

What is the 4 year rule for planning?

In England it no longer exists for building work. The four-year period was replaced by a single ten-year period on 25 April 2024. Four years still applies in Wales.

Sources