GOV.UK guidance on enforcement and post-permission matters confirms a local planning authority has discretionary power to issue an enforcement notice where it believes a breach of planning control has occurred and considers it expedient to act, that recipients generally have 28 days to appeal to the Secretary of State, and that non-compliance once the notice takes effect, with no appeal outstanding, is a criminal offence carrying an unlimited fine.

When a council can issue a notice

A local planning authority has a discretionary power to issue an enforcement notice where it believes a breach of planning control has occurred, for example a conservatory built without the planning permission it needed, and where it considers it expedient to act, having regard to the development plan and other material considerations. This is a discretionary power, not an automatic consequence of every unauthorised structure, so a council can decide the breach does not warrant formal action, though it is not required to reach that conclusion.

The time limits for taking action

Councils do not have an unlimited window to act against operational development such as a conservatory. Current guidance gives a ten-year time limit for enforcement action where the development was substantially completed on or after 25 April 2024, and the previous four-year limit continues to apply where the development was substantially completed before that date. Once the relevant time limit has passed without enforcement action being taken, the development generally becomes immune from enforcement, which is the basis for the lawful development certificate route covered elsewhere on this site.

What the notice must say

An enforcement notice has to let the recipient understand exactly what, in the council’s view, constitutes the breach of planning control, and what steps are required to remedy it or what activities must stop. Guidance requires the notice to be written in plain English and to be accompanied by information about the right to appeal, so a recipient is not left having to work out independently what the council is objecting to or what it wants done about it.

The 28-day appeal deadline

A recipient generally has 28 days to appeal an enforcement notice to the Secretary of State, in effect to a planning inspector. This deadline is applied strictly, without the flexibility that applies to some other planning time limits, so identifying and meeting it is one of the most time-critical steps in responding to a notice, rather than something that can be dealt with at a more relaxed pace alongside gathering evidence or seeking advice.

What an appeal does

Lodging a valid appeal within the deadline suspends the enforcement notice, meaning it does not take effect while the appeal is being decided; the recipient does not have to comply with it, and does not commit an offence, during that period. This gives a genuine practical reason to appeal rather than simply comply immediately, wherever there is a real basis to challenge the notice, since appealing preserves the position while the dispute is resolved.

What happens without a successful appeal

If the compliance period set out in the notice passes without it being complied with, and there is no outstanding appeal, failing to comply becomes a criminal offence. A person convicted faces an unlimited fine, with the court required to have regard to any financial benefit that has accrued or appears likely to accrue from the breach. Separately, the council can use default powers to carry out the required work itself and recover the cost from the property owner, rather than relying solely on prosecution to secure compliance.

FAQs

Is a council required to issue an enforcement notice for every unauthorised conservatory?

No. Issuing a notice is a discretionary power, exercised where the council believes a breach has occurred and considers it expedient to act.

How long does a council have to take enforcement action?

Ten years for operational development substantially completed on or after 25 April 2024, and four years for development substantially completed before that date.

How long is there to appeal an enforcement notice?

Generally 28 days to the Secretary of State, applied strictly with no discretion to accept a late appeal.

What happens if the notice isn’t appealed or complied with?

Non-compliance once the notice takes effect is a criminal offence carrying an unlimited fine, and the council can also carry out the required work itself and recover the cost.

Bottom line

A planning enforcement notice against an unauthorised conservatory has to clearly set out the breach and the required remedy, and carries a strict 28-day deadline to appeal to the Secretary of State; a valid appeal suspends the notice, but failing to comply once it takes effect, without an outstanding appeal, is a criminal offence with an unlimited fine. This is general information, not legal advice on a specific notice; a planning solicitor should be consulted urgently given how strict the appeal deadline is.

Sources

This guide draws on the following primary sources, current as of 22 September 2026:

• GOV.UK, “Enforcement and post-permission matters”

Related guides

Compare Conservatories is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not legal or planning advice on any specific property — always confirm requirements directly with your local planning authority.