Prior approval: what the council may and may not consider

Prior approval is a narrow check, not a general planning judgement. The permission already exists, granted by the General Permitted Development Order, and the local planning authority's job is limited to deciding whether prior approval is required for the specific matters that class lists, and if so whether it is granted. Anyone looking at the prior approval scope of matters for a conversion scheme should start by reading the class text itself, because the list in one class tells you nothing about the list in another.

That narrowness is the whole value of the route. It is also the thing most often ignored, by applicants who submit a full design rationale nobody asked for and by authorities that refuse on grounds the class does not mention.

What the route actually is

A class in Schedule 2 of the Order grants permission for a described operation or change of use, subject to limits and conditions. One of those conditions, in many classes, is that before beginning the development the developer must apply to the authority for a determination as to whether prior approval is required for certain matters.

Three things follow. The development plan does not govern the decision in the way section 38(6) of the Planning and Compulsory Purchase Act 2004 governs a planning application. The authority must have regard to national policy only so far as it is material to the listed matters. And the authority cannot substitute its own view of whether the development is a good idea.

The right can still be absent altogether. Article 4 directions remove rights across a defined area, and designations mean Article 2(3) land removes rights entirely for several classes. Check both before spending anything.

Why the list is closed

The matters are set out in the class, and the courts have treated that list as exhaustive. An authority considering something outside it is going beyond its powers.

The lists differ a great deal. A class dealing with the change of use of a commercial building to dwellings will typically name transport and highways impacts, contamination risk, flooding risk, the effect of noise from nearby commercial premises on the future occupiers, and the provision of adequate natural light in all habitable rooms, with further matters where the building sits in a conservation area or where fire safety information is required. A class dealing with an upward extension will instead name design and external appearance, because there the physical result is what matters.

So the practical instruction is simple. Print the current text of the class. Work through each listed matter in order. Address every one, and address nothing else.

The matters that come up most often

Four recur across the residential conversion classes, and they are where applications fail.

Contamination is the one most often underestimated. A former commercial or industrial building being converted to homes introduces a sensitive end use, and authorities will expect a preliminary risk assessment rather than an assertion. A land contamination assessment prepared by a suitably qualified and experienced person, following the recognised investigation standards, is what satisfies this. A desk study alone may be enough where the history is clean, and it rarely is on an industrial estate.

Flooding is answered from the published flood map together with, where the building sits in Flood Zone 2 or 3, a flood risk assessment addressing safe access, egress and finished floor levels.

Transport and highways impacts turn on parking, servicing and access rather than on general traffic generation, and the evidence is usually a short statement with a parking survey where on-street capacity is contested.

Noise from commercial premises is assessed in the direction most people forget. The question is the effect of existing commercial noise on the intended occupiers of the new dwellings, not the effect of the dwellings on anyone else.

The clock, and deemed approval

Many Part 3 classes give the authority 56 days from the receipt of a valid application. If the authority has not notified the applicant of its determination within that period, the development may proceed in accordance with the details submitted.

Two cautions. The period is set by each class, so check it rather than assuming 56 days. And the clock only runs from a valid application, which means every document the class requires has to be there. An authority that later says a required plan was missing will also say the period never began, and the deemed approval never happened.

Keep the evidence. A dated submission receipt, a copy of everything sent, and a note of the fee payment are what settle the argument if it arises two years later when the building is occupied.

Conditions

An authority granting prior approval may impose conditions, but they must connect to the matters for which approval was required. A condition about contamination remediation on a class where contamination is a listed matter is sound. A condition about affordable housing contributions, on a class that says nothing about them, is not.

The Order also imposes its own conditions directly, including time limits for completion in several classes. Those bite whether or not prior approval was required, and missing a completion deadline can leave a partially converted building without the benefit of the permission at all.

When the authority goes outside the list

It happens, usually in the form of a refusal reason drawn from a local plan policy that has nothing to do with the listed matters. Occasionally it takes the form of a request for information the class does not require, which stalls the application while the clock is disputed.

The answer is rarely to argue at length by email. Write once, politely, identifying the matter in the class text and asking the officer to confirm which listed matter the request relates to. If the refusal comes anyway, appeal. Inspectors deal with this regularly and are direct about the limits of the regime.

Building first and arguing later is the expensive version. An enforcement notice can be appealed on ground (a), which brings the deemed application on a ground (a) appeal into play, but that puts the whole scheme into the planning merits arena you were trying to avoid.

Responding to a refusal

Three routes exist and they suit different problems.

1. Resubmit, where the refusal identified a fixable evidence gap within a listed matter. There is no statutory bar on a second application.
2. Appeal, where the refusal reason falls outside the class or where the evidence is sound and the judgement is wrong. Check the appeal period on the decision notice, because it is shorter than the general six months for planning appeals.
3. Apply for full planning permission, where the scheme has drifted outside the class limits anyway. That brings the development plan back into play, and a planning statement addressing policy properly becomes necessary rather than optional.

Pick the route on the refusal reason, not on which feels quicker. An appeal against a refusal that was actually correct on a listed matter wastes months.

You can check the constraints on the building with the postcode on PlanScope before deciding which route the class allows.

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.