Time Limit for Retrospective Planning Permission

Retrospective planning permission is a legal route used when development or building work has already been carried out without first obtaining the required planning approval. It allows the property owner or developer to regularise unauthorised works by applying for permission after the fact. While councils have the power to grant approval retrospectively, this does not mean it is guaranteed and the risk of enforcement action increases the longer unauthorised development goes unaddressed.

Understanding the time limits for retrospective planning permission is essential if you find yourself in this situation. Whether you inherited a property with unknown alterations, accidentally overlooked planning rules, or proceeded without realising consent was needed, acting within the relevant timeframes can help protect you from serious consequences.

What Is Retrospective Planning Permission?

Retrospective planning permission is an application made to a local planning authority for development that has already taken place without prior consent. This could include building an extension, changing the use of land, installing signage, or making alterations to a listed building. Planning law in the UK allows councils to consider these applications just like any other, assessing the impact against current planning policy.

If permission is granted retrospectively, the development is then considered lawful. If it is refused, the council may require the work to be reversed or removed through enforcement action. The key issue is timing because if too much time passes, enforcement may no longer be legally possible.

Time Limits for Enforcement

The rules around retrospective planning permission are closely tied to planning enforcement time limits, which are set by law under the Town and Country Planning Act 1990. These time limits determine how long a local authority has to take action against unauthorised development.

There are two main enforcement periods.

The first is four years for operational development. This includes physical building work such as extensions, outbuildings or structural alterations. If the work has been substantially completed for four years without any enforcement action, it becomes immune from planning control and the council cannot take action.

The second is ten years for material change of use. This includes changing a residential property into a business, subdividing it into flats or operating a house in multiple occupation without permission. If the unauthorised use continues for ten years without interruption or enforcement, it may become lawful through time.

Once these time limits have passed, the development becomes exempt from enforcement action and you may apply for a Lawful Development Certificate instead of retrospective planning permission. This certificate confirms the legality of the development based on its longevity rather than planning policy compliance.

When Should You Apply Retrospectively?

If you have carried out work that requires planning permission but did not apply beforehand, it is best to act as soon as possible. You can submit a retrospective planning application to the local planning authority using the same process as any other application. The fact that the work has already been done does not prevent approval, but it may affect how the council views the development, especially if it has caused complaints or breaches local planning policies.

If the development has taken place within the last four or ten years depending on the type, the council may still issue an enforcement notice requiring you to remove or alter the work. Applying retrospectively before any enforcement begins gives you the chance to explain the reasoning behind the development and demonstrate how it meets planning objectives.

What If Enforcement Action Has Already Started?

If the council becomes aware of an unauthorised development, it may send a planning contravention notice or issue a formal enforcement notice. Once a valid enforcement notice is issued, you cannot apply for retrospective planning permission. Instead, you must appeal the notice through the Planning Inspectorate.

This process allows you to argue that permission should be granted or that enforcement is not justified. You must submit the appeal within the time limit stated on the enforcement notice, usually 28 days. Ignoring enforcement action can lead to legal penalties including fines or court orders.

What About Listed Buildings or Conservation Areas?

If you have carried out unauthorised work to a listed building, there is no time limit on enforcement. Even if the work was completed many years ago, the council can still take legal action. Listed building consent is separate from planning permission and failing to obtain it can lead to prosecution.

In conservation areas, development is also more tightly controlled. Retrospective applications are still possible but councils take a stricter approach to ensure that changes do not harm the character of the area.

Lawful Development Certificate vs Retrospective Planning

If the development is old enough to fall outside the enforcement time limits of four or ten years, you do not need to apply for retrospective planning permission. Instead, you can apply for a Certificate of Lawful Existing Use or Development. This certificate confirms that the development is lawful purely because of the passage of time and not because it complies with planning policy.

You must provide strong evidence such as photographs, sworn statements, council tax records or tenancy agreements to prove how long the development or use has existed. If the council is satisfied, they will issue the certificate offering legal protection from future enforcement.

Real-World Example

A homeowner in Gloucestershire built a rear conservatory in 2018 without planning permission. In 2023, during the sale of the property, a buyer’s solicitor requested evidence of approval. The owner checked with the local authority and confirmed that the structure exceeded permitted development limits. Since it had been in place for over four years with no enforcement action, they applied for a Lawful Development Certificate, providing photos and dated invoices from the original builder. The council approved the certificate, confirming the conservatory was now lawful.

Conclusion

Retrospective planning permission can resolve unauthorised development but timing is everything. If work has been carried out without permission, you typically have four years for building works or ten years for changes of use to apply before enforcement becomes a risk. After this period, you may be able to secure a Lawful Development Certificate instead. Acting quickly, understanding the rules, and working with your local authority can help protect your property and avoid costly legal problems.