Article 3(5), limitations and conditions in the GPDO

Article 3 of the Town and Country Planning (General Permitted Development) (England) Order 2015 grants the permission, and it takes it away again in three ways. Article 3(2) makes every grant subject to the exceptions, limitations and conditions written into the relevant class in Schedule 2. Article 3(4) stops the Order overriding a condition on an existing planning permission. And article 3(5) withdraws the permission altogether where the building the rights attach to was built unlawfully, or where the existing use the rights depend on is unlawful.

Those three provisions decide more prior approval arguments than the class text itself. An architect reading a class needs to separate what defines it from what is attached to it, because the consequence of getting each one wrong is different.

The difference between limitations and conditions

A limitation describes the development the class permits. The 4 m depth for a single-storey rear extension on a detached house, the 3 m for other houses, the 4 m height limit, the restriction on the side of a house fronting a highway: all of these say what the class covers.

A condition is something you must do, or refrain from doing, to keep the benefit of the grant. Using materials of a similar appearance to the existing house. Obscure glazing and restricted opening on an upper-floor side window. Setting a roof extension back 20 cm from the eaves. Applying for a prior approval determination before work starts.

The practical difference shows up when things go wrong. Exceed a limitation and the development was never permitted development at all, because it falls outside the description of the class. Breach a condition and the result is the same in law, which surprises people: the permission granted by the Order is a conditional permission, so failing to comply means the development is not authorised by the Order and becomes development carried out without planning permission.

Nobody serves a breach of condition notice for a rear extension built in the wrong brick. The council enforces against the extension.

What article 3(5) requires

Article 3(5) is the lawfulness gateway, and it is the first question to ask on any conversion or reuse. Where the class grants permission in connection with an existing building, the rights do not apply if the building operations that created that building were unlawful. Where the class grants permission in connection with an existing use, the rights do not apply if that use is unlawful.

This is why a barn erected without the right agricultural notification, or an office created by an unauthorised change of use, cannot simply be converted under a Part 3 class. The rights never arose.

Lawfulness can be restored by time. Once the operational development or the change of use has become immune from enforcement, it is lawful, and article 3(5) no longer bites. Enforcement time limits for breaches occurring on or after 25 April 2024 in England are ten years for both operational development and changes of use, following the amendments made by the Levelling-up and Regeneration Act 2023, so check when the breach occurred before assuming the old four-year rule applies. The clean answer is a certificate of lawfulness for the existing use or development, which converts an argument into a document.

Our note on the Class Q structural works test shows how the lawfulness question and the building condition question get tangled together on barn schemes.

Consequences of breaching a condition

Treat a breach as producing unauthorised development, and plan accordingly. Three routes are then open.

1. Put it right, so that the development complies with the condition as built.
2. Apply for full planning permission for the development as it stands, which is a retrospective application under section 73A of the Town and Country Planning Act 1990.
3. Do nothing and wait for immunity, which leaves the building unmortgageable and unsaleable in the meantime and offers no protection from an enforcement notice in the interim.

The second route is the usual one, and it is not a formality. A council assessing a retrospective application considers the development on its merits against the development plan, and the fact that it would have been permitted development had the condition been met carries some weight as a fall-back but does not decide the case.

Enforcement against a condition breach

Where the development is unauthorised, the council can serve an enforcement notice requiring the breach to be remedied, and the notice can require removal rather than alteration. Appeal rights follow under section 174, and the grounds include that planning permission ought to be granted.

Councils in practice ask for correction first. An obscure glazing condition breached on a side window is usually resolved by fitting the right glass, and a materials condition by rendering or reclaiming. Where the breach is structural, such as a roof extension built flush to the eaves rather than set back, the remedy is expensive and the conversation becomes adversarial quickly.

Conditions attached to prior approvals

Parts 3, 6, 16 and 20 work through prior approval, and the requirement to apply is itself a condition of the class. Starting work before the determination, or before the 56-day period expires without a decision, means the development is not permitted.

Prior approval classes also carry their own completion conditions. Several of the Part 3 residential conversion classes require development to be completed within three years of the date of prior approval, and Part 6 agricultural classes carry their own timing and use restrictions. Diarise the date on the decision notice, because a conversion half finished at the deadline has no fall-back.

The approval itself frequently attaches further conditions on top of the class ones, dealing with contamination, noise, flooding or transport depending on the class. Read those separately from the Schedule 2 text. The agricultural prior notification route under Part 6 shows how the class conditions and the approval conditions stack.

Evidencing compliance

The only formal way to confirm that works are lawful is a certificate of lawfulness, applied for under section 192 for proposed development or section 191 for something already built. A certificate is a decision on fact and law rather than a planning judgement, and it binds the council.

Short of that, keep the evidence a future purchaser's solicitor will ask for:

Most disputes on sale are about materials and glazing, and both are solved by photographs taken at the time.

Common conditions people overlook

Side-facing windows above ground floor level are the single most missed condition on householder extensions, and the requirement runs to both obscure glazing and restricted opening below 1.7 m above floor level. The 20 cm eaves set-back on roof extensions comes second.

Solar installations carry siting and removal conditions that people forget once the panels are up, including the requirement to minimise effect on the external appearance of the building and on amenity, and to remove equipment when no longer needed. The projection limits are covered in domestic solar panels and the 200 mm projection limit.

An Article 4 direction removes rights entirely rather than conditioning them, so check for one before working through Schedule 2 at all. And where any part of the analysis is finely balanced, say so in the planning statement rather than asserting compliance the council has not confirmed.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.

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.