What happens when a prior approval lapses
Class MA, Class Q and the Part 20 classes require completion within three years, not a start. What happens when the date passes with the works unfinished.
A prior approval lapse time limit works differently from the one attached to a planning permission, and the difference catches out experienced developers. A planning permission requires development to begin within three years. Several of the most useful permitted development classes require the development to be completed within three years of the prior approval date. Beginning is not enough. A half built conversion on the day the period expires has no consent for the rest of it.
That single distinction is the reason schemes under Class MA, Class Q and the Part 20 upward extension classes need a programme that works backwards from a completion date rather than forwards from a start.
The time limit attached to each class
The General Permitted Development Order 2015 attaches conditions class by class, and the completion requirement is not universal. Read the class you are relying on rather than assuming a pattern.
The classes most often used for conversion and intensification carry a completion condition running three years from the date of the prior approval. Class MA, for commercial to residential conversion, and Class Q, for agricultural buildings to dwellings, both work this way. The Part 20 classes, covering upward extensions and demolition and rebuild, carry the same style of condition.
Other parts work differently again. Some classes require development to be begun within a period, some require notification of completion, and the telecommunications rights in Part 16 carry their own conditions and timescales, as our note on Part 16 masts and prior approval sets out.
Practical consequences worth writing on the programme:
- Diarise the expiry date from the prior approval decision notice, not from the date you submitted.
- Treat the date as a completion deadline unless the class text says otherwise.
- Check whether the class defines completion, and if it does not, work to a defensible definition such as the building being capable of occupation.
- Record the date on which you consider the development complete, with photographs.
When development is treated as begun
For the classes that require a start rather than a completion, the test is the one used across the planning system: a material operation as defined in section 56(4) of the Town and Country Planning Act 1990.
That covers work of construction, digging a trench for foundations, laying out or constructing a road, laying underground mains or pipes to the foundation trench, and in the case of a change of use, the change itself.
The operation has to be genuine and referable to the approved scheme. Work carried out under a different consent, or on a part of the site outside the prior approval, does not begin the development. Neither does preparatory work that would have been lawful anyway, such as clearing vegetation.
But note that for a class requiring completion, all of this is beside the point. Starting in month 34 of a 36 month period simply means you run out.
Evidence of a lawful start
Where the class requires a start, the evidence you keep is what proves it later, and disputes surface years afterwards when a purchaser's solicitor asks.
Keep dated photographs from fixed viewpoints, the contractor's daily records and invoices, delivery notes, and any building control inspection record covering the excavation. A statutory declaration from the person who carried out the work is worth obtaining while they still remember it.
Where the position is likely to be questioned, apply for a lawful development certificate under section 191 of the 1990 Act confirming that the development was lawfully begun. That is the only route to a binding answer, and it is far easier to obtain while the site records are fresh.
Effect of a lapsed approval on the scheme
When a completion deadline passes with the works unfinished, the permitted development right no longer authorises what remains.
The building itself does not become unlawful retrospectively where what was done was carried out within the period and in accordance with the approval. What you lose is the authority to finish. Continuing afterwards is development without planning permission, and the council can serve an enforcement notice requiring the works to be removed or the building restored.
The position is worse where the scheme was a change of use that had not taken place. A building converted structurally but never occupied for the approved use may have no lawful use at all beyond its original one, and the structural works may then be unauthorised as well because they were carried out for a purpose the approval no longer supports.
Sale becomes hard at this point. A buyer's solicitor sees a lapsed approval and an incomplete building, and the usual answer is to require a fresh consent before completion.
Reapplying under the same class
A fresh prior approval application is often possible, and the obstacle is rarely the application itself. It is requalification.
Class MA is the clearest example. The right depends on the building having been in a qualifying commercial use for a period before the application and on it having been vacant for a continuous period immediately before the application. A building part converted, part occupied by contractors and no longer in its former commercial use may not satisfy those conditions any more.
Class Q depends on the building having been in agricultural use on a specified date and on the building being capable of conversion without substantial rebuilding. Works already carried out can undermine both limbs, because a structure that has been opened up and partly rebuilt may no longer be the building the class protects.
Before submitting again, take three steps:
- Re-test every condition of the class against the site as it now is, not as it was.
- Consider whether a full planning application is the safer route, accepting the fee and the eight or thirteen week period in exchange for a permission that requires a start rather than a completion.
- Check whether an Article 4 direction has been made over the area in the meantime, because a direction removes the right entirely.
Changes to the order between applications
The Order is amended frequently, and the version that applies is the one in force when the application is made. Classes have been added, narrowed, given new floorspace limits and given new conditions, and rights have been removed on designated land.
So a scheme that qualified three years ago may not qualify now. Check the current consolidated text, not a summary or an old advice note, and check whether the class still exists in the form you relied on. Our note on how the prior approval procedure works covers the mechanics of the application itself, and for upward extensions the limits in Class AA have their own conditions.
Where the local plan has been adopted in the interim, that matters too. Prior approval decisions under some classes require specified matters to be considered, and a new plan policy can change how the council assesses them on a second application.
Programming to avoid the problem
Treat the completion date as the fixed point and work backwards.
Fix the building contract and the funding before submitting the prior approval, so the 56 day determination period is not dead time. Order long lead items, particularly windows, glazing and structural steel, on the strength of the approval rather than after it. Build in contingency for the discoveries that always come with conversions: unexpected structure, contamination, asbestos, a drainage connection that does not exist.
Then ask the honest question at the start. If the programme needs 30 months of construction on a 36 month consent with a conversion of uncertain condition, a full planning application with a three year period to begin may be the better instrument even though it costs more and takes longer to obtain.
This is general guidance, not legal advice, and a lawful development certificate is the only formal way to confirm that works are lawful. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope can draft the supporting documents, including a Planning Statement, and the report index shows what a conversion usually needs.
PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Is a prior approval the same as planning permission for time limits?
No. A planning permission normally requires development to begin within three years. Several permitted development classes, including those used for commercial to residential and agricultural conversions and for upward extensions, require the development to be completed within three years of the prior approval date. Read the class text rather than assuming.
Does a lapsed prior approval make completed work unlawful?
Not usually. Work carried out within the period and in accordance with the approval stays lawful. What lapses is the authority to finish, so continuing afterwards is development without permission and can be enforced against. A change of use that never took place is a harder position, because the approved use may never have become lawful.
Can I simply reapply under the same class?
Sometimes, but requalification is the obstacle. Class MA depends on a qualifying previous use and a period of vacancy, and Class Q depends on agricultural use on a specified date and on conversion without substantial rebuilding. Part completed works can defeat those conditions, so re-test every limb against the site as it now is.
How do I prove development was lawfully begun?
Keep dated photographs from fixed viewpoints, contractor records and invoices, delivery notes and any building control inspection records. Where the point is likely to be disputed, apply for a lawful development certificate under section 191 of the Town and Country Planning Act 1990 while the site records and witnesses are still available.
Could a full planning application be safer than prior approval?
On a long or uncertain conversion, often yes. A permission requires development to begin within three years and imposes no completion deadline unless a condition says otherwise. The trade is a fee, a longer determination period and a full assessment, against the risk of running out of time part way through construction.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.