What an extension of time agreement really costs
Extensions of time look free because no fee is payable. They cost you the non-determination appeal right, the planning guarantee refund and the holding costs nobody counts.
An extension of time agreement carries no fee, which is exactly why it looks free and is not. Signing one removes your right to appeal against non-determination for the length of the extension, disapplies the fee refund the planning guarantee would otherwise give you at 26 weeks, and converts a statutory deadline into a date the authority has already shown it struggles to meet.
None of which means you should refuse. On most applications an extension is the sensible course, because an appeal against non-determination usually produces a worse outcome more slowly. The point is to price it, then agree a short one with a date on it.
Why an authority asks
The statutory determination periods are eight weeks for householder and minor applications, thirteen for major applications and sixteen where environmental impact assessment applies. Authorities measure their performance against those periods, and an application determined within an agreed extension counts as determined in time.
That is the honest answer to why the request arrives, and it is not a discreditable one. A case officer facing a consultee response due next month, a committee date three weeks after that, and a section 106 to draft, has a real choice between asking for an extension and issuing a refusal to protect the statistics. The extension is the better outcome for both of you.
What matters is that the incentive is not symmetrical. The authority gains a performance statistic and removes a refund liability. You give up two legal rights and take on holding costs. Neither side is behaving badly; you are simply the only one paying.
No fee, and the rights you give up
| What changes | Effect of a written extension |
|---|---|
| Fee payable | None |
| Appeal against non-determination | Deferred to the end of the agreed period |
| Planning guarantee fee refund at 26 weeks | Disapplied |
| Performance statistics | Determination counted as in time |
| Holding costs | Continue to accrue |
| Option or contract deadlines | Unchanged, and now closer |
The refund point is the one most often overlooked. Where the authority has already been sitting on the application for twenty weeks, an extension signed at that stage gives away an entitlement that was six weeks away, and the note on the fee refund at 26 weeks sets out what that entitlement is worth and how it is claimed.
Losing the appeal against non-determination
The right of appeal under section 78 of the Town and Country Planning Act 1990 arises when the statutory period, or any agreed extended period, expires without a decision. An extension therefore postpones it.
In most cases that costs you little in substance, because a non-determination appeal is a poor remedy. You arrive at the Planning Inspectorate with no officer report, no committee resolution and no clear statement of the authority's case, and the inspector determines the application afresh on evidence the authority assembles late. Timescales for written representations, let alone a hearing or inquiry, generally exceed the delay you were complaining about.
The exception is a case where the authority is not going to grant permission whatever happens and everyone knows it. There, the delay is the only thing standing between you and a decision you intend to appeal anyway, and an extension simply defers the start of the real process by however long you agree to.
Performance statistics, and how they shape behaviour
Two mechanisms sit behind the request. Authorities report on the proportion of applications determined within the statutory period or an agreed extension, and persistent underperformance can lead to designation, which allows applicants to make certain applications directly to the Secretary of State instead of the authority.
Knowing that helps in the conversation. An authority with a designation risk has a strong interest in extensions, and it also has a strong interest in avoiding non-determination appeals. That gives you room to ask for something in exchange: a firm committee date, publication of the officer report by a stated day, or a commitment that no further information will be requested.
Ask for that in the same email as you agree the extension. Afterwards there is nothing to trade.
Holding costs, funding and option agreements
This is where the real money is, and it varies so much by scheme that no general figure is meaningful. What is worth doing is calculating your own before you reply.
The lines to add up: interest or opportunity cost on the land value for the extension period, professional fees for the team staying mobilised, any site security or maintenance cost, and the cost of programme slip at the far end where a construction start moves out of a season or a sales period.
Then look at the contractual dates. An option agreement with a fixed expiry, a conditional contract requiring permission by a date, or a funding facility with a drawdown condition can each turn a routine eight week extension into a transaction failure. Check those before you agree anything, because a promoter who has agreed an extension past an option expiry has a much larger problem than a slow council.
Where refusing an extension is the better call
Four situations.
- The officer recommendation will be negative and the case is going to appeal regardless.
- A contractual or funding date makes further delay unacceptable.
- The authority has already had one extension and has not delivered what it said it would.
- There has been no substantive engagement at all, so there is no evidence the extra time will be used.
In those cases, decline politely, say why, and confirm that you will consider an appeal if no decision is issued. That last sentence changes the urgency without threatening anything, and it is usually enough.
Where you do decline and the authority then refuses in haste, the costs position at appeal becomes relevant, and unreasonable behaviour in the handling of an application can support an application for costs, as covered in how costs awards at appeal are assessed.
Negotiating a short, dated extension
Write the agreement rather than accepting a form of words. Four elements:
A specific end date, not a number of weeks from an unstated start. A statement of what will happen by then, naming the consultee response, the committee date or the section 106 stage. A statement that no further extension will be agreed without a fresh discussion. And confirmation of what the authority will do if the date slips, even if that is only to notify you a week in advance.
Six to eight weeks is usually enough. Anything longer than twelve weeks should be a planning performance agreement with a proper programme rather than an extension, and if the authority wants that, it should be structured and, where a fee applies, priced accordingly.
Keep a record of every extension, its date and what was promised. On a phased site, that record is the evidence base for the next negotiation, and the 66 report types by category show which supporting documents most often trigger the consultee delays that extensions are asked for in the first place.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.
Drafting supporting documents early is the least costly way to avoid the delay that leads to an extension request. See PlanScope pricing: one free report, £50 per report, or Professional for unlimited reports. 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 there a fee for an extension of time?
No fee is payable, which is why the request looks costless. What you give up is the right to appeal against non-determination for the length of the extension, the fee refund the planning guarantee would provide at 26 weeks from validation, and the holding costs that continue to accrue while the application sits undetermined.
Why do councils ask for extensions?
Because an application determined within an agreed extended period counts as determined in time for performance reporting, and persistent underperformance can lead to designation, which lets applicants take certain applications directly to the Secretary of State. The request is usually reasonable on its face; the incentive behind it is simply not symmetrical.
Is an appeal against non-determination a good alternative?
Usually not. You reach the Planning Inspectorate with no officer report, no committee resolution and no clear statement of the authority's case, and the timescales often exceed the delay complained of. The exception is a case that is going to be refused and appealed anyway, where the delay is the only thing in the way.
What should be asked for in exchange?
A firm committee date, publication of the officer report by a stated day, or a commitment that no further information will be requested. Ask in the same message in which you agree the extension, because afterwards there is nothing left to trade. An authority concerned about its performance figures has a real interest in agreeing.
When should an extension be refused?
Where the recommendation will be negative and the case is going to appeal anyway, where a contractual or funding date makes delay unacceptable, where a previous extension was not honoured, or where there has been no substantive engagement so nothing suggests the time will be used. Decline politely and note that an appeal will be considered.
How long an extension is reasonable?
Six to eight weeks is usually enough for a named consultee response or a committee cycle. Anything beyond about twelve weeks should be a planning performance agreement with a written programme rather than an open extension. Always agree a specific end date rather than a number of weeks from an unstated starting point.
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.