Retrospective Planning Permission: Applying After Building Without Consent

You can apply for retrospective planning permission after building without consent — the application is assessed on exactly the same basis as a normal application, and the council cannot refuse simply because work has already been done. The fee is the same (£258 for householder). However, if refused, the council can issue an enforcement notice requiring you to undo the work. Key time limits apply: after 4 years for buildings (or 10 years for changes of use), development may become immune from enforcement. This guide explains how to apply, the risks, and the important time limits.

What Is Retrospective Planning Permission?

Key Retrospective Planning Facts (England, 2024)

• Application fee: same as normal (£258 householder)
• 4-year immunity: operational development and change of use to single dwelling
• 10-year immunity: other changes of use and breach of conditions
• First resubmission within 12 months: free of charge
• Lawful Development Certificate (existing): £258 to confirm immunity from enforcement
• Council cannot refuse solely because work has already been done

What is a Lawful Development Certificate? A Lawful Development Certificate (LDC) confirms that a development is lawful — either because it complies with permitted development rules (proposed LDC, £120) or because it has become immune from enforcement through the passage of time (existing LDC, £258). It provides legal certainty and is useful for property sales.

Retrospective planning permission is simply a planning application submitted after development has already taken place. The law explicitly allows for this — Section 73A of the Town and Country Planning Act 1990 states that planning applications can be made for development that has already been carried out.

A retrospective application is processed in exactly the same way as a normal application. The council assesses it against the same policies and material considerations. The fact that the development already exists is not a reason to refuse or approve it — the application must be determined on its planning merits.

Key Point: It's Legal to Apply Retrospectively

There's a common misconception that building without permission is automatically a criminal offence. In most cases, it isn't. Carrying out development without planning permission is not a criminal offence (with some exceptions for listed buildings and protected trees). It's a breach of planning control, which is a civil matter dealt with through enforcement.

The exceptions where it is a criminal offence include:

• Unauthorised works to a listed building (listed building consent is separate from planning permission)
• Unauthorised works to protected trees
• Breaching an enforcement notice
• Displaying unauthorised advertisements in certain cases

When Should You Apply Retrospectively?

You've Been Told to Apply

The most common trigger is receiving a letter from the council's enforcement team asking you to submit a retrospective application. This is usually the first step in the enforcement process — the council gives you the opportunity to regularise the situation before taking formal action.

You Want to Sell Your Property

When selling a property, your solicitor will check that all development has the necessary planning permissions and building regulations approval. Unauthorised development can:

• Delay or collapse a sale
• Reduce the sale price
• Make the property unmortgageable
• Require indemnity insurance (an additional cost)

Applying for retrospective permission before selling is almost always the better option.

You Want Peace of Mind

Even if no one has complained, unauthorised development remains a risk. Neighbours change, enforcement policies evolve, and the sword of Damocles hanging over your property isn't comfortable.

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How to Apply for Retrospective Planning Permission

The Application Process

Applying retrospectively follows the same process as a normal application:

1. Complete the application form on the Planning Portal (planningportal.co.uk)
2. Submit plans and drawings showing the development as built
3. Pay the standard fee (same as a normal application — e.g., £258 for householder)
4. Include supporting documents as required by the validation checklist

On the application form, you'll tick the box indicating the development has already been carried out. This triggers the retrospective process.

What Drawings Do You Need?

You'll typically need:

• Site location plan (1:1250 or 1:2500)
• Block plan (1:200 or 1:500)
• Existing plans (showing the property before the development)
• As-built plans (showing the development as it currently exists)
• Elevations of the development

Since the development already exists, the "proposed" plans are actually the "as built" plans. Some councils find this confusing, so label your drawings clearly.

The Decision

The council has the usual 8 weeks (householder) or 13 weeks (major) to determine the application — the same timeframes as a normal application. Understanding why applications get refused is important context: the council cannot simply refuse because work has been done, but the same policy grounds still apply. Possible outcomes:

• Approved: The development is regularised. You'll receive a decision notice granting retrospective permission, possibly with conditions.
• Refused: The development remains unauthorised. The council may proceed with enforcement action. You have the right to appeal the refusal.
• Approved with conditions: Conditions may require modifications to the development as built. For example, obscure glazing in a window, landscaping, or boundary treatment changes.

What If Retrospective Permission Is Refused?

If your retrospective application is refused, the development remains unauthorised and you face several risks:

Enforcement Action

The council can issue an enforcement notice requiring you to:

• Remove the unauthorised development entirely
• Modify the development to make it acceptable
• Cease an unauthorised use

You have the right to appeal an enforcement notice to the Planning Inspectorate. The appeal process effectively becomes a fresh planning application assessment.

The Costs of Non-Compliance

Failing to comply with an enforcement notice is a criminal offence carrying:

• Fines in the magistrates' court of up to £20,000
• Unlimited fines in the Crown Court
• In extreme cases, the council can enter your land and carry out the works themselves, then charge you for the cost

The Time Limits: The 4-Year and 10-Year Rules

Time limits play a crucial role in enforcement. If enough time has passed since the breach of planning control, the council loses the power to take enforcement action.

The 4-Year Rule

The council has 4 years to take enforcement action for:

• Building operations (construction of a building or extension)
• Change of use to a single dwelling

After 4 years from substantial completion of the building works (or the start of the use as a dwelling), the council can no longer take enforcement action. The development becomes immune from enforcement.

You can apply for a Lawful Development Certificate (LDC) to formally confirm this immunity. The LDC provides legal certainty and is essential when selling the property.

The 10-Year Rule

For all other breaches of planning control, the time limit is 10 years. This includes:

• Changes of use (other than to a single dwelling)
• Breaches of planning conditions
• Engineering operations

Important Caveats

The time limit rules come with significant caveats:

• Deliberate concealment: If you deliberately concealed the breach (for example, building inside an existing structure so it wasn't visible), the council can apply to the magistrates' court for a Planning Enforcement Order that resets the clock. This was introduced to tackle people who deliberately hid developments until the time limit expired.
• Continuous breach: The breach must have been continuous for the full period. If you built an extension, demolished it, then rebuilt it, the clock restarts.
• Evidence: You need to prove the development has existed for the required period. Photographs, utility bills, council tax records, satellite imagery, and sworn statements from neighbours can all help.

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Common Scenarios

Extension Built Without Permission

You built a rear extension that you believed was permitted development, but it exceeds the allowed dimensions. Your options:

1. Apply for retrospective planning permission (£258)
2. If it's been more than 4 years, apply for a lawful development certificate (£258)
3. If refused, modify the extension to comply with permitted development limits

Change of Use Without Permission

You converted your garage into a bedroom without applying for planning permission. If this constitutes a material change of use, you may need retrospective permission. However, many garage conversions don't require planning permission if the garage is attached and the external appearance doesn't change significantly.

Outbuilding Too Large for Permitted Development

You built a garden building that exceeds the permitted development limits (perhaps it's too tall, too close to the boundary, or covers too much of the garden). Apply retrospectively — many councils will approve if the impact on neighbours is acceptable.

Business Run From Home

You started a business from home that's grown beyond what's incidental to the residential use. A change of use may have occurred, requiring planning permission. This is particularly relevant if customers visit the property, deliveries are frequent, or the business dominates the property's character.

Tips for a Successful Retrospective Application

1. Act promptly when contacted by the council — cooperation goes a long way
2. Be honest in your application — don't try to minimise what's been built
3. Commission accurate drawings of the development as built
4. Address neighbour concerns proactively — if neighbours complained, try to resolve issues
5. Consider modifications — offering to change elements (such as adding obscure glazing or reducing height) can turn a refusal into an approval
6. Get professional advice — a planning consultant can assess your chances and advise on the best strategy

Frequently Asked Questions

Is building without planning permission a criminal offence?

In most cases, no. Carrying out development without planning permission is a breach of planning control, which is a civil matter. However, it becomes a criminal offence if you breach an enforcement notice, carry out unauthorised works to a listed building, or damage protected trees.

Can I get a mortgage on a property with unauthorised development?

It's difficult. Most mortgage lenders require confirmation that all development has the necessary permissions. Options include: applying for retrospective permission, obtaining a lawful development certificate (if time limits have passed), or purchasing indemnity insurance (which some lenders accept for minor breaches).

How far back can the council investigate planning breaches?

The council can investigate at any time, but their power to take enforcement action is limited by the 4-year rule (building works) and 10-year rule (changes of use and condition breaches). After these periods, the development becomes immune from enforcement.

Will the council definitely take enforcement action if they find out?

Not necessarily. Enforcement is discretionary — the council has no obligation to act on every breach. They prioritise cases based on the severity of harm caused. A minor extension that doesn't affect neighbours may never attract enforcement action, while a development causing significant harm will be prioritised.

Can I apply for retrospective permission for part of the development?

Yes. You can apply to regularise part of a development while agreeing to modify or remove other parts. This pragmatic approach often leads to a better outcome than an all-or-nothing application.

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Further Reading

Related Guides

• How to Appeal a Planning Decision
• Permitted Development Rights Explained
• Planning Enforcement: When Rules Are Broken
• What Are Material Planning Considerations?
• Conservation Areas and Planning
• How Much Does Planning Permission Cost?
• Can Planning Permission Be Refused?

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