Prior approval or planning permission: the real difference

Prior approval versus planning permission is a procedural question with commercial consequences. Prior approval is not a lesser form of planning permission. The permission has already been granted by Parliament through the General Permitted Development Order, and the council is left with a short, closed list of matters it may examine before the work starts. A full planning application is the opposite: the authority weighs the whole proposal against the development plan and any other material consideration.

That difference in scope drives everything else, including how long the council has, what it can refuse on, and what you are left holding if it says no.

What prior approval actually tests

Permitted development rights are granted by the Town and Country Planning (General Permitted Development) (England) Order 2015. Many of the more valuable classes, particularly the change of use classes in Schedule 2 Part 3, are granted subject to a requirement that the developer first applies to the authority for a determination as to whether its prior approval is required for specified matters.

The council is answering a narrow question. Not whether the development is acceptable in principle, because that has been decided already, but whether the listed impacts can be managed. Paragraph W of Part 3 sets out the procedure: what the application must contain, who must be consulted, the publicity required and the time limits.

Compare that with a full application under section 62 of the Town and Country Planning Act 1990, determined under section 70 against the development plan and material considerations. An officer assessing a full application can refuse on design, on the loss of a commercial unit, on housing mix, on amenity for future occupiers, on almost anything that is material.

The matters an authority may consider

Each class has its own list. Under Class MA, the change from commercial, business and service use in Class E to dwellinghouses, the matters include transport and highways, contamination risk, flooding risk, noise from commercial premises, the provision of adequate natural light to habitable rooms, and the effect of losing a ground floor use in a conservation area. Under Class Q, the conversion of agricultural buildings to dwellinghouses, the list includes transport and highways, noise, contamination, flooding, whether the location makes the dwelling impractical or undesirable, the design and external appearance of the building, and the provision of natural light.

Read the class text before you assume an issue is in scope. The lists differ and they have been amended repeatedly, so work from the current consolidated text on legislation.gov.uk rather than from a printout.

Two consequences follow for anyone converting buildings. Evidence has to be targeted at the listed matters and nothing else: a noise impact assessment dealing with the commercial neighbours, a desk study and, where the screening suggests it, intrusive work under a land contamination assessment. And there is no point spending money arguing that the scheme is a good use of the site.

The 56 day clock and deemed consent

For most Part 3 prior approvals the authority has 56 days beginning with the day immediately after the valid application is received. If it neither grants nor refuses within that period, the development may proceed provided it is carried out in accordance with the details submitted. That is the deemed consent, and it is the single biggest procedural difference from a full application.

Larger home extensions under Part 1 Class A run on a different, shorter timetable through the neighbour consultation scheme, and the developer must wait for the authority to notify the outcome.

There is no equivalent on a full application. The eight week period for a minor application and thirteen weeks for a major application give you a right of appeal against non-determination, not a permission.

Fee figures are indexed and revised, so check the current schedule on the Planning Portal or in the fees regulations before you budget.

Conditions attached to each route

A full permission carries whatever conditions the authority imposes, tested against the six tests in national policy. Prior approval works differently. The class itself contains conditions and limitations that bind the development whether or not anyone writes them down, for example the requirement in several classes that the development is completed within three years of the date of prior approval.

The authority may also impose its own conditions, but only ones reasonably related to the subject matter of the prior approval. A condition on a Class MA approval controlling window specification to address noise is within scope. A condition requiring a contribution to open space is not, because that subject was never before the authority.

That constraint cuts both ways. It keeps the process quick. It also means you cannot negotiate your way out of a problem by offering mitigation on something outside the list, which is a frequent frustration where a scheme fails on one matter and the applicant is willing to fix something else entirely.

Appeal rights and what they get you

A refusal of prior approval is appealable to the Planning Inspectorate under section 78, as is a refusal of a full application. The difference is the ground on which the inspector decides. On a prior approval appeal the inspector is confined to the same listed matters. The appeal cannot be used to argue that the conversion is a good idea.

Householder appeals run on a twelve week expedited procedure, while most other written representations appeals must be lodged within six months of the decision. An appeal against non-determination of a full application is available once the statutory period expires, though it is rarely the best move when the officer is close to a recommendation.

Refusals on matters outside the scope

It happens. An officer, under pressure from consultees, refuses a Class Q application on grounds that read like a full application: the isolated location, the effect on the character of the countryside generally, the loss of agricultural land. Where that ground sits outside the class list, it is not a lawful reason for refusal and an appeal has a strong prospect.

Check the decision notice against the class text line by line before deciding how to respond. Sometimes a resubmission with better evidence on the in-scope matter is quicker than an appeal, particularly where the authority has flagged a genuine gap, such as a missing structural appraisal showing the agricultural building can take the conversion without substantial rebuilding.

Keep the paperwork clean either way. Ownership certificates and agricultural holdings notices are served on prior approval applications exactly as they are on full applications, and a defective certificate is a reason to invalidate, as set out in our guide to ownership certificates A to D.

Using a permitted development fallback

A live prior approval, or an unchallenged right to carry out work under the Order, is a material consideration in a later full application. The argument runs that the authority should compare the proposed scheme against what could lawfully be built anyway, rather than against the existing building.

Inspectors ask whether there is a real prospect that the fallback would actually be implemented. A genuine prospect carries weight. A theoretical right the owner has no intention of exercising carries little. Evidence helps: a costed scheme, a contractor's programme, a certificate of lawfulness confirming the right exists.

Fallback arguments also interact with amendments. Where a permission is already in place and the change is modest, the question becomes whether to vary a condition or apply for a minor material amendment, which we cover in section 73 or section 96A.

An Article 4 direction removes permitted development rights in a defined area, so the first check on any prior approval route is whether one applies to your street.

PlanScope can draft the supporting documents for either route from your postcode and a few answers about the building, including the noise, contamination and transport evidence a prior approval application needs. Start by browsing the report types and see which are flagged for your site.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. A lawful development certificate is the only formal way to confirm that works are lawful. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.