Prior approval: the application that is not quite one

A prior approval application meaning is narrower than it looks. It is not an application for planning permission. The permission already exists, granted by the permitted development order, and what you are applying for is a determination of whether the authority's approval is required for a short list of specified matters. Everything outside that list is off the table, including design, policy compliance and whether the authority thinks the scheme is a good idea.

For a landlord converting commercial space or a barn, that distinction is the whole value of the route. It also carries a trap that catches people every year: a prior approval does not confirm that your scheme is permitted development in the first place.

What the term covers

Several classes in the permitted development order grant permission subject to a condition that the developer first applies to the local planning authority for a determination as to whether prior approval is required for stated matters.

The authority then does one of three things. It says prior approval is not required, in which case you build. It says prior approval is required and grants it, usually with conditions limited to the specified matters. Or it refuses, and the development is not permitted.

There is a right of appeal against refusal, decided on the same narrow basis. An inspector considering a refused prior approval looks at the specified matters and nothing else, which makes these appeals faster and more predictable than most.

Where it comes from

The procedure sits inside Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015, class by class, with the matters and the procedure set out in each class and in the accompanying paragraphs.

The familiar examples cover very different ground.

The lists are not interchangeable, and they change. Class Q limits on the number of dwellings and the floorspace involved were amended in 2024, and the order has been amended repeatedly since 2015, so read the consolidated text on legislation.gov.uk rather than a summary.

The matters an authority may consider

This is where prior approval applications are won.

An officer raising design objections to a Class MA conversion is raising something outside the list, and saying so politely and early usually resolves it. Equally, an applicant who ignores one of the listed matters has handed the authority its refusal reason.

Address each matter head on, with evidence proportionate to the scale.

• Contamination, on a former commercial or agricultural building, normally needs a desk study, and the Contaminated Land Assessment is the document that carries it. Land contamination work requires a suitably qualified and experienced author, and PlanScope's draft is a starting point for that professional rather than a substitute.
• Noise from commercial premises, where the new dwellings sit above or beside a working unit, needs a Noise Impact Assessment with measured background levels, not a statement that the use is quiet.
• Flooding, where the site is in Flood Zone 2 or 3, needs a Flood Risk Assessment addressing the proposed residential use.
• Transport and highways usually turns on parking and servicing, and on a town centre site the sustainable location argument does most of the work.
• Natural light in habitable rooms is a drawing exercise: window areas, room depths and any rooms relying on borrowed light.

The deemed approval period

Each class sets a period within which the authority must notify its determination. For the Part 3 change of use classes that period is 56 days from a valid application, and for the larger home extension route it is 42 days.

If the authority fails to notify a determination within the period, the development may proceed in accordance with the application. That is a real and regularly used route, and it is the reason the validity of the submission matters so much. A deemed approval on an application the authority never accepted as valid is no approval at all.

Three practical rules follow. Submit everything the class requires, including the plans and the specific statements, because an incomplete submission does not start the clock. Get a dated acknowledgement. And do not rely on an oral assurance that the authority will not meet the date.

An illustrative office to flats conversion

The following is illustrative. A first and second floor office suite of around 400 m², vacant since the start of the year, previously in commercial use for several years, in a town centre outside a conservation area, with a restaurant at ground floor level.

The qualifying conditions for the class come first: the floorspace is within the cap, the building has been vacant for the required continuous period, the prior use qualifies for the required period, the building is not listed, and no Article 4 direction applies. Each of those needs evidence, and the vacancy period needs dated proof rather than an assertion.

The prior approval submission then addresses the listed matters: a noise assessment dealing with the restaurant extract and late servicing, a contamination desk study, a parking and cycle storage statement, a flood screening note, and a natural light drawing for every habitable room.

Nothing in that submission needs to argue that flats are appropriate in principle. If the matters are addressed and the qualifying conditions are met, the authority's discretion is spent.

What it is often confused with

Three distinctions matter.

A prior approval is not a full planning application. The authority cannot refuse on grounds outside the class, and it cannot require a planning statement arguing the principle.

It is also not a confirmation that the development is permitted development. The authority's determination addresses the specified matters only, and if a qualifying condition turns out to have been unmet, there was never any permission. Where there is real doubt, a lawful development certificate for proposed development under section 192 of the Town and Country Planning Act 1990 is the instrument that settles it.

And it is not available where the development would be subject to environmental impact assessment, since permitted development rights are excluded for such schemes, a limit discussed in environmental information under the EIA Regulations.

Checking the position for a site

Work through five things in order.

1. The current text of the relevant class, including every qualifying condition and exclusion.
2. The authority's Article 4 direction map, since directions removing commercial to residential rights are common in central and university areas.
3. Listed status, scheduled monuments and any other designation that disqualifies the class.
4. Evidence for every date-based condition: vacancy, prior use, and the dates the building was last occupied.
5. The current fee for the application, which is set nationally and indexed annually, so check the published schedule.

Get that right and the route is quick, limited and predictable. Enter your postcode on PlanScope to see which supporting documents a prior approval application for your building is likely to need.

This is general guidance, not legal advice: check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.