Extensions of time and the eight week deadline

A planning application extension of time is a written agreement between you and the council to move the determination deadline, and it is the most consequential document most applicants sign without reading. The eight week period for a minor application comes from the Development Management Procedure Order 2015, runs from the day after validation, and is a duty on the authority rather than a promise to you. When week seven arrives and the case officer emails asking for four more weeks, you are being asked to give up a right in exchange for something. Whether the exchange is worth it depends entirely on where the application has got to.

For a self-builder on a borrowed deposit, that calculation is not academic.

The statutory periods and when they start

Three periods matter. Eight weeks for householder and other minor applications. Thirteen weeks for major development, meaning ten or more dwellings, 1,000 m² or more of floorspace, or a site of 0.5 hectares or more. Sixteen weeks where the application is accompanied by an environmental statement.

Each runs from the day after the authority holds a valid application. Validation is the trigger, not submission, and an application held for a fortnight over a missing certificate simply starts late. Check the validation date on the public register rather than counting from the day you uploaded.

The period can be extended, but only in one way: by a period agreed in writing between the applicant and the authority. There is no power for the council to extend it unilaterally, and silence on your part is not agreement.

What an extension of time agreement actually is

It is a short written agreement naming a new date. That is all. It does not change the application, the policy against which it is assessed, the fee, or the officer's recommendation. What it changes is when your appeal right under section 78 of the Town and Country Planning Act 1990 arises, and how the decision is counted in the authority's published performance statistics.

Two practical points often missed. The agreement should name a specific date rather than a duration, because "four weeks from the receipt of the highways response" is unenforceable in practice. And an extension can be agreed more than once, which is how applications end up running for nine months in a sequence of polite emails.

Why officers ask, and when to say no

Authorities are measured on the proportion of applications determined within the statutory period or an agreed extension. An extension turns a late decision into an on-time one, so there is an institutional reason behind the request, and officers are open about it when asked.

That does not make the request unreasonable. Common and legitimate reasons: a statutory consultee has not responded, the lead local flood authority has asked for additional drainage information, you have submitted amended plans that need re-consultation, a section 106 agreement is being drafted, or the case is going to a committee whose next meeting falls after the deadline.

Agree where one of these applies and the officer is working towards an approval. Before deciding, read the consultee responses on the file, because they tell you whether the delay is doing useful work or whether a refusal is being drafted.

Refuse, politely and in writing, where:

• The officer has already indicated that the scheme is unacceptable in principle and no amendment is under discussion.
• Nothing is outstanding and the delay is caseload rather than process.
• Your programme has a fixed date, such as a mortgage offer or a seasonal survey window, that the extension would miss.
• You have already agreed one extension and the reason given for the second is the same as the first.

Say what you are doing and why: that you are content for the application to be determined on the material before the authority, and that you would rather have a decision than a date.

The appeal against non-determination

Where the period expires with no decision and no agreed extension, section 78 gives a right of appeal to the Secretary of State on the ground that the authority has failed to determine. Nothing is deemed refused. The application simply sits undecided until you appeal, and you can leave it sitting for a considerable time if that suits you.

The appeal is lodged with the Planning Inspectorate and usually proceeds by written representations for smaller schemes. The deadline is generally six months from the expiry of the period, though shorter periods apply to some routes, so check the current guidance for the type of application rather than relying on a remembered figure.

The authority then produces a statement setting out what it would have decided and why, which is often the first time you see a reasoned position.

The risks of appealing rather than waiting

An appeal removes the case from the officer who was two weeks from recommending approval. That is the main risk, and it is a real one.

Three others worth weighing. The inspector decides on the planning merits as at the date of the appeal decision, so a policy change or a new local plan adoption in the intervening months can help or hurt. You lose the ability to negotiate conditions and amendments, because the scheme is fixed as submitted and an inspector cannot approve a different one. And a section 106 agreement cannot be completed by the authority during an appeal in the ordinary way, which complicates anything requiring obligations.

The cost side is usually modest for written representations, but the time is not. An appeal frequently takes longer than the delay you were escaping, which is the uncomfortable arithmetic set out in more detail in appealing non-determination or waiting it out.

Where the application has stalled and the authority will neither determine nor explain, the appeal is the only lever you have. Use it as a lever rather than a reflex: a courteous email saying that you will appeal on a stated date unless a decision is issued frequently produces a decision.

The planning guarantee and the designation regime

Two background mechanisms shape authority behaviour.

The planning guarantee is a commitment that no application should take more than 26 weeks, backed by a refund of the application fee where the authority fails to determine within that period and no extension has been agreed. Signing an extension removes the entitlement, which is one more reason to think before agreeing a second one.

The designation regime under section 62B of the 1990 Act allows the Secretary of State to designate authorities that perform poorly on speed or on the proportion of decisions overturned at appeal, after which applicants in that area may apply directly to the Secretary of State for major development. Because agreed extensions count as on-time determinations, the speed measure gives authorities a direct interest in collecting them.

None of this is a reason to assume bad faith. It is a reason to read the request as what it is.

Recording the agreed date

Keep it simple and keep it written:

1. Reply by email, confirming the new date as a calendar date.
2. State what the extension is for, in one sentence, so there is a record of the reason.
3. Say that you do not agree to any further extension without a fresh discussion.
4. Diarise the date and diarise the appeal deadline that follows from it.
5. Save the exchange with the application documents.

A clear Planning Statement at submission reduces the chance of this arising at all, because most extensions are consumed by information the authority could have had on day one. Scoping properly up front is the least costly intervention available, and it is worth taking time to scope the documents before you submit.

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.