How Long Does Planning Permission Last?

In most cases, planning permission in the UK lasts for three years from the date it is granted. This means you must start the approved development within three years or the permission will expire and you'll need to reapply. The same applies whether you have full or outline planning permission, although outline permission involves a two-stage process and slightly different timings.

This three-year period gives homeowners and developers time to prepare for construction, finalise finances, arrange contractors or deal with any unexpected hurdles. However, simply having permission does not guarantee indefinite approval—it’s a countdown clock from the moment it’s granted.

How to 'Lock In' Permission

To lock in or activate planning permission, you need to make a “material start” on the project before the three-year deadline. A material start must be more than just moving a plant pot or putting up a fence—it typically includes:

• Digging foundations

• Pouring concrete footings

• Drainage works

• Setting up any structural elements (steel or timber framing)

These works must be in accordance with the approved plans. Once started, the permission becomes “live” and does not expire, even if you complete the build later. It's also good practice to take photos and keep records of the date and nature of the work, just in case the council questions whether you started in time.

Does Planning Permission Expire?

Yes—if no work has started within the three-year window, planning permission automatically lapses. Once expired, the permission no longer has legal weight and cannot be used to carry out development. At that point, you’ll need to submit a new application, which may or may not be approved again depending on current planning policies and changes in local guidelines.

This is particularly important if you gained permission under more favourable rules or in an area undergoing change—waiting too long might risk losing your opportunity.

How Do You Keep Planning Permission Alive?

To keep permission alive, you must start meaningful work before the deadline. This can include:

• Starting excavation

• Laying part of the foundations

• Installing drainage

• Carrying out engineering work related to the structure

Once started, permission remains valid indefinitely, even if work is paused. However, councils do have the power to serve a completion notice if they believe a project is being deliberately delayed.

If you're unsure whether your early work will count, you can apply for a Lawful Development Certificate to confirm that the permission is still in effect.

What Does an Expiry Date Mean on a Planning Application and What Constitutes a Start Date?

The expiry date on your decision notice is the deadline to commence development. It does not mean the build must be finished—just that work must have started.

The start date is the day on which the first physical act of building occurs in line with your approved plans. This could be digging trenches for footings, installing foundations or other significant preparatory work.

Minor work like fencing, painting or moving soil usually doesn’t count. If there’s any doubt, it’s worth getting professional advice to ensure you meet the legal definition of commencement.

Does Planning Permission Add Value?

Yes—having planning permission can significantly increase the value of a property, especially if the permission is for an extension, a loft conversion or a new dwelling on part of your land. It shows buyers or investors that the potential for development exists, saving them time, money and uncertainty.

Even if the permission is close to expiry, it can still be a valuable selling point. Some developers specialise in acquiring land with expired or soon-to-expire permissions and reapplying under new plans.

However, expired permission has little to no value, so timing is everything if you’re looking to maximise the return on your property.

Can You Extend Planning Permission Once It’s Granted?

You used to be able to apply to extend planning permission, but that rule changed in 2013 in most parts of the UK. Now, if your permission is approaching expiry and work hasn't started, you’ll need to submit a new application. This isn’t technically an extension—it’s a fresh process that may be assessed under updated planning policies, so previous approval doesn’t guarantee future success.

That said, if you’ve already made a material start before the expiry, your permission remains active—no need to reapply.

What If I Have Outline Planning Permission?

If you’ve been granted outline planning permission, you must:

1. Submit your ‘reserved matters’ application (the detailed follow-up) within three years

2. Start work within two years of receiving approval for the reserved matters

This two-stage process is often used for larger developments or when a landowner wants to establish potential use before designing the full project.

Can You Sell Planning Permission?

Yes! While you can’t technically “sell” the permission itself, you can sell the land or property that benefits from the permission—and this often commands a higher price. For example, a house with approved plans for an extension or a garden plot with permission to build can be very attractive to developers or buyers looking for ready-made opportunities.

Planning permission is tied to the land, not the individual—so the new owner can proceed with the approved plans as long as the permission is still valid.

What Happens If Only Part of the Work Has Been Done?

If you've made a material start—like digging foundations—but then stopped, your permission remains valid. However, leaving the project incomplete could attract a completion notice from the council if they believe the delay is unreasonable or harmful to the local area.

That said, most councils won’t intervene unless neighbours complain or the incomplete structure becomes an eyesore or danger. But it’s good practice to keep a record of work done and maintain the site properly.

Does Planning Permission Lapse If Ownership Changes?

No—planning permission stays with the land, not the person. If you sell your home or development plot after getting planning permission, the new owner inherits the same rights and conditions. This makes it easier for buyers to pick up where you left off, and is why permission can boost property value even if no work has started.