What Is Retrospective Planning Permission?

Retrospective planning permission is a planning application made after development has already taken place or after a change of use has already started.

​

It is commonly needed where:

​

• Building work was carried out without realising permission was required

• A builder or previous owner said permission was not needed

• A project was assumed to be permitted development, but may not be

• Work was built differently from approved drawings

• A garage, outbuilding or extension has been converted without approval

• A property use has changed without planning consent

• The council has received a complaint or opened a planning enforcement case

​

In England, the Town and Country Planning Act 1990 allows planning permission to be granted for development carried out before the date of the application. This is why retrospective planning permission is often referred to as a Section 73A application.

​

​

The quick answer

 

Retrospective planning permission is a way to ask the council to approve work after the event.

​

It may be suitable where:

​

• The work would probably have been acceptable if applied for beforehand

• The development can be justified against planning policy

• The design, size, use or location can be explained properly

• Any planning harm can be reduced or controlled

• The council is willing to consider regularising the position

​

It is not a guaranteed approval.

​

The council will still assess the application in the normal way. The Planning Portal confirms that even if a local authority asks for a retrospective application, this does not mean permission will automatically be granted.

​

​

When might you need retrospective planning permission?

 

You may need retrospective planning permission if you have already carried out work such as:

​

• A house extension

• A loft conversion

• A front dormer

• A balcony or roof terrace

• A garage conversion

• A garden room or outbuilding

• A porch

• A fence, gate or boundary wall

• A driveway or access alteration

• A shopfront or external alteration

• A new dwelling or annex

• A change of use

• An HMO conversion

• Airbnb or short-term let use

• Conversion of a property into flats

• Works in a conservation area

• Works affecting a listed building or its setting

​

It can also apply where the work had permission, but was not built in accordance with the approved plans.

​

​

Common reasons retrospective planning issues arise

 

Retrospective planning problems often happen because:

​

• The homeowner did not know planning permission was required

• The builder gave informal advice that turned out to be wrong

• Online permitted development guidance was misunderstood

• The property had restrictions or removed permitted development rights

• The site was in a conservation area

• The property was a flat or maisonette

• Previous extensions had already used up permitted development limits

• The work changed the appearance of the property

• The work affected parking, access or neighbours

• A neighbour complained to the council

• The issue came up during a property sale or remortgage

​

TOP TIP
If you think a planning mistake may have been made, do not ignore it. It is usually better to understand the position early, before enforcement action, sale delays or further building work make the problem worse.

​

​

Is retrospective planning permission legal?

 

Yes, retrospective planning permission is a recognised part of the planning system.

​

It does not mean the council will automatically approve the work, but it does provide a formal route for trying to regularise unauthorised development.

​

A local planning authority may also invite a retrospective application through an enforcement warning notice where it considers that unauthorised development has a reasonable prospect of being acceptable in planning terms. If the requested application is not submitted by the deadline, the council may decide to take further enforcement action.

​

​

What happens if retrospective planning permission is approved?

 

If the application is approved, the development may become authorised in planning terms.

​

This can help:

​

• Regularise the work

• Reduce enforcement risk

• Create a formal planning record

• Help with a future sale or remortgage

• Reassure solicitors, buyers and lenders

• Confirm what has been accepted by the council

​

The approval may include planning conditions.

​

These could relate to:

​

• Materials

• Use of the building

• Parking

• Landscaping

• Privacy screening

• Hours of operation

• Removal of certain features

• Restrictions on future changes

​

​

What happens if retrospective planning permission is refused?

 

If the application is refused, the council may consider enforcement action.

​

This could mean you are asked to:

​

• Remove the unauthorised work

• Change the development

• Stop the unauthorised use

• Submit a revised application

• Appeal the decision or enforcement notice

• Restore the property to its previous condition

​

The Planning Portal explains that if a retrospective application is refused, the local authority can issue an enforcement notice requiring the owner to put things back as they were.

​

IMPORTANT POINT
Retrospective planning permission should not be treated as a shortcut. The council will still consider planning policy, design, neighbour impact, highways, conservation issues and the character of the area.

​

​

Retrospective planning permission vs Lawful Development Certificate

These are different routes.

​

Retrospective planning permission may be needed where:

​

• Planning permission was required

• Work has been carried out without approval

• A use has changed without consent

• The council needs to assess planning merit

• The proposal may need conditions to make it acceptable

• The development falls outside permitted development

​

A Lawful Development Certificate may be more suitable where:

​

• The work did not need planning permission

• The work was permitted development

• The use or development has become lawful over time

• You need formal confirmation of lawfulness

• The issue is legal proof rather than planning merit

​

The Planning Portal describes a Lawful Development Certificate as a legal document confirming the lawfulness of existing or proposed building work, use, operations or other planning matters.

​

​

Common retrospective planning examples

 

Garage conversions

A garage conversion may create a retrospective planning issue if:

​

• The garage door was replaced with a wall and window

• The front elevation changed

• Parking was affected

• A planning condition required the garage to remain as parking

• The garage became separate living accommodation

• The property is in a restricted estate or sensitive planning area

​

Garden rooms and outbuildings

A retrospective issue may arise where the outbuilding is:

​

• Too high

• Too large

• Too close to a boundary

• Forward of the main house

• Used for sleeping accommodation

• Used as a separate annex

• Used commercially

• Located in the grounds of a listed building

​

​

Loft conversions

A loft conversion may need retrospective planning review if it includes:

​

• A front dormer

• A large rear dormer over permitted limits

• A roof terrace

• A balcony

• A mansard roof

• Work in a conservation area

• Work to a flat or maisonette

• Changes not matching previous approval

​

​

Change of use

Retrospective planning permission may be needed where a property has already been used as:

​

• An HMO

• Flats

• Airbnb or short-term let accommodation

• A separate annex

• A commercial unit

• A mixed-use property

• A business operating from a residential property

​

Change of use issues can be more complex because the council is not just looking at physical building work. It is also looking at how the property is being used.

​

​

What drawings and information are normally needed?

 

A retrospective planning application usually needs clear information showing what has actually been built or changed.

​

This may include:

​

• Site location plan

• Existing and as-built floor plans

• Existing and as-built elevations

• Roof plans where relevant

• Block plan

• Photographs of the completed work

• Planning statement or supporting explanation

• Design and access statement where required

• Heritage statement if listed or in a conservation area

• Parking or highways information where relevant

• Evidence about when the work was carried out

• Details of materials and external finishes

​

The drawings must show the real position, not an idealised version of what should have been built.

​

​

Should you stop work?

 

If work is still ongoing and you discover a possible planning problem, it is sensible to pause and get advice.

​

This is especially important where:

​

• The council has contacted you

• A neighbour has complained

• The work is highly visible

• The property is listed or in a conservation area

• The work affects structure, access or safety

• The development may need to be changed

• Continuing could make the planning position worse

​

Stopping work does not fix the planning issue, but it may reduce risk while the position is reviewed.

​

​

Retrospective planning and building regulations

 

Retrospective planning permission is not the same as building regulations approval.

​

Planning deals with:

​

• Use

• Size

• Appearance

• Design

• Neighbour impact

• Highways

• Conservation

• Local planning policy

​

Building regulations deal with:

​

• Structure

• Fire safety

• Insulation

• Ventilation

• Drainage

• Stairs

• Electrical safety

• Energy performance

• Construction standards

​

You may need retrospective planning permission and separate building control regularisation or building regulation approval.

​

​

How PAS can help

 

Planning Application Services (PAS) can help homeowners understand whether retrospective planning permission is needed and what the best route may be.

​

We can review:

​

• The property address

• What has been built or changed

• Whether planning permission was likely to be required

• Whether permitted development may have applied

• Whether a Lawful Development Certificate may be a better route

• Whether a retrospective planning application is needed

• Whether the work may need changes before submission

• Whether building regulations, structural design or party wall matters also apply

​

We can then help prepare the drawings, supporting information and application if a retrospective submission is the right way forward.

​

​

When paid planning consultancy is useful

 

Paid planning consultancy is especially useful for retrospective issues because the wrong step can make the situation worse.

​

It can help where:

​

• You have received a council letter

• A neighbour has complained

• You are worried work was carried out without approval

• You are selling and the buyer’s solicitor has raised a planning query

• You bought a property with missing planning paperwork

• You need to know whether an LDC or planning application is better

• You need drawings of what has already been built

• You need a practical view before approaching the council

​

A proper desktop review can help identify the safest route before money is spent on the wrong application.

​

​

Need help with retrospective planning permission?

 

If you are asking “What is retrospective planning permission?”, there is a good chance you are dealing with work that has already started, already been completed, or has now been questioned.

​

Before contacting the council or submitting an application, PAS can help you understand:

​

• Whether there is likely to be a planning breach

• Whether retrospective planning permission may be needed

• Whether a Lawful Development Certificate may be more suitable

• Whether the work needs drawings

• Whether the proposal is likely to raise planning concerns

• Whether changes may be needed before applying

• What the next practical step should be

​

​

Next Steps:

 

Tell Us What You Need

Use our enquiry form to explain what has been built, changed or questioned.

PAS can review the position and guide you towards the most sensible next step.

​

​

Planning Consultancy

Choose paid planning consultancy if you need a proper desktop review before deciding how to deal with a retrospective planning issue.

This is useful for:

​

• Extensions

• Loft conversions

• Garage conversions

• Garden buildings

• Outbuildings

• HMOs

• Airbnb use

• Change of use

• Works in conservation areas

• Existing works without paperwork

​

​

Plans and Drawings

If retrospective drawings are needed, PAS can prepare plans showing the work as built, so the application is clear and properly presented.

​

​

Retrospective Planning Applications

If retrospective planning permission is the right route, PAS can help prepare and submit the application to the local planning authority.

​