Summary
Planning permission normally lasts three years, but it only survives if development is lawfully commenced within that time. Lawful commencement means carrying out qualifying building works after any pre-commencement planning conditions have been approved. If you cannot prove that sequence, the permission will be lost – even if work took place on site.
This article explains how long planning permission lasts, but more importantly, why permissions fail in the real world and how people unknowingly lose perfectly good approvals. Most homeowners ask how long planning permission lasts after they have already secured approval. By that point, the clock is already ticking. The better question – the one that actually protects projects – is this: “What needs to happen, in what order, for this permission to stay alive?”
Planning permission is not a certificate you can safely store away. It is a conditional legal right that only remains valid if it is activated correctly. Many permissions lapse not because owners delay, but because they assume progress on site equals legal progress. It doesn’t.
For most full planning permissions in England, the Local Planning Authority imposes a condition requiring development to begin within three years of the decision date. This is the standard position in law. However, the decision notice is the controlling document. If a different time limit applies, it will be stated clearly in the conditions. General advice, blog posts and assumptions are irrelevant if they conflict with the wording of your actual permission. Once the time limit expires without lawful commencement, the permission automatically lapses. There is no extension, no grace period and no discretion for the council to keep it alive.
A common misunderstanding is that development must be completed within three years. That is not the case. You only need to begin development within the time limit. Once a permission has been lawfully implemented, it does not expire simply because construction pauses or takes longer than expected. The problem is that what planning law considers a valid “start” is far narrower than most people think.
In planning law, development is considered to have begun when a material operation forming part of the approved scheme has taken place. This is set out in Section 56 of the Town and Country Planning Act 1990.
In simple terms, this means physical works that clearly relate to the approved development, such as digging foundation trenches in the correct location, pouring concrete footings, installing underground services that form part of the scheme, or carrying out demolition where demolition is integral to the approved plans.
Actions that feel like progress – appointing a builder, clearing the site, ordering materials, fencing land – do not count. They have no legal weight when it comes to keeping a planning permission alive. But even carrying out the right kind of work is not enough on its own.
Most planning permissions include conditions. Some of these conditions say that certain details must be approved before any development begins. These are known as pre-commencement conditions, and they are the single most common reason permissions expire unexpectedly.
If your permission says “no development shall commence until…” and you start work before the council has formally approved those details, the law treats that work as unlawful. From the council’s perspective, it is as if nothing happened. The clock keeps running. This is where many homeowners go wrong. Foundations can be in the ground, money can be spent, and yet the permission can still expire because the sequence was wrong.
Once a planning permission has been lawfully commenced, it is often described as extant – meaning it remains legally alive. Crucially, councils do not usually confirm extant status at the time works begin. The issue typically arises later, when the permission is relied upon during a property sale, refinancing, neighbour complaint, enforcement investigation, or further planning application.
At that point, the question is not whether work took place, but whether it can be proven that lawful commencement occurred within the time limit. The burden of proof lies entirely with the person relying on the permission. Dated photographs, condition discharge approvals, contractor records and clear documentation suddenly become critical. Many permissions that appear safe exist in a grey area until they are tested – and that is when problems surface.
Some people attempt a small amount of work shortly before the expiry date to keep a permission alive. Sometimes this succeeds. Often, it creates long-term risk. If the work is minimal, poorly documented, unrelated to the approved scheme, or carried out before pre-commencement conditions were discharged, the permission’s extant status becomes vulnerable. Years later, that vulnerability can derail a sale or trigger enforcement issues. From experience, rushed starts made under time pressure are one of the most common sources of future planning disputes.
Outline planning permission follows a different structure and is frequently misunderstood. Typically, it requires reserved matters to be submitted within a set period, followed by a further deadline to commence development once those matters are approved. Missing either deadline causes the permission to lapse. More importantly, outline permission only approves the principle of development. Many of the difficult issues – layout, design, access, neighbour impact – are resolved later. Outline consent is not a guarantee that a buildable scheme will follow.
Where development requires both planning permission and listed building consent, each consent has its own lifespan. It is entirely possible for one to remain valid while the other expires, preventing lawful development from proceeding. This often happens in conservation areas, where permissions are treated as separate paperwork exercises rather than a single coordinated approval strategy.
Planning permission can add significant value to a property, but only if it is live, implementable and defensible. Buyers, surveyors and solicitors increasingly examine whether permissions are close to expiry, whether conditions were discharged correctly, and whether lawful commencement can be evidenced. A permission that looks attractive on paper but cannot be relied upon in practice is often discounted – and sometimes treated as a liability rather than an asset.
In practice, planning permissions do not fail because people forget the deadline. They fail because conditions are misunderstood, sequencing is wrong, budgets drift away from the approved design, or the project evolves while the permission does not. Time is rarely the real problem. Misalignment is. Handled strategically, three years is generous. Handled casually, it disappears far faster than most people expect.
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