How to Extend Planning Permission

In the UK, full planning permission typically lasts for three years from the date it is granted. If development has not lawfully commenced within that timeframe, the permission will expire. For anyone not ready to start building, this can create considerable pressure and uncertainty. You might have faced funding delays, design revisions, or market changes that made immediate construction unviable. So what can you do if your three-year window is coming to an end?

Extending planning permission is not as simple as it once was. Prior to 2013, it was possible to apply for a time extension under transitional arrangements, but these were removed from legislation over a decade ago. Today, the options are limited and depend heavily on your ability to act before permission expires. Understanding the rules around extensions, implementation, and reapplication is essential for developers, self-builders, and homeowners with long-term plans.

Why Planning Permission Expires After 3 Years

Under Section 91 of the Town and Country Planning Act 1990, full planning permission automatically includes a condition requiring development to begin within three years. This time limit ensures that developments are delivered in a timely fashion and that planning decisions remain relevant to current policies and local needs. If no work starts within this period, the permission lapses and becomes invalid.

Outline planning permissions have a slightly different timeframe. You typically have three years to submit reserved matters applications and then two further years to commence development from the date of their approval. These rules are set nationally, and local planning authorities cannot usually extend them at their discretion.

Can You Extend Planning Permission?

There is no formal process to extend an unimplemented planning permission once it has been granted. If your permission is approaching its expiry date and work has not started, you have two main options:

The first and most secure method is to begin development before the expiry date, thereby implementing the permission and keeping it alive indefinitely. This means carrying out a “material start” on site, which could involve digging and pouring foundations, constructing walls, or installing drainage infrastructure. The start must be meaningful and lawful, with any pre-commencement conditions discharged in advance.

The second option is to submit a new planning application for the same or a similar scheme before the original permission expires. If the proposal still complies with local and national policy, it may be approved again without major changes. However, it will be assessed afresh, so any updates to planning policy or local conditions could result in new objections or a different decision.

What Does 'Material Start' Mean?

To preserve planning permission beyond the three-year window, a lawful start must be made. The courts and planning policy have established clear guidance on what constitutes a material start. This includes significant physical work on site, such as laying foundations, trenching, or beginning structural work. Merely clearing the site or storing materials is not enough.

It is essential that any pre-commencement conditions attached to the original permission have been properly discharged. For example, you may need to submit a construction management plan or details of external materials before any work starts. Failing to discharge these conditions can result in enforcement action and may invalidate the start, even if physical work has been carried out.

For larger developments, beginning work on just one part of the site can be sufficient to implement the permission across the whole area, provided it aligns with the approved plans and phasing strategy. Many developers use this tactic to preserve permission while delaying the bulk of the build.

Can Section 73 Be Used to Extend Time?

Section 73 of the Town and Country Planning Act 1990 allows applicants to vary or remove conditions attached to an existing planning permission. However, it cannot be used to extend the time limit for commencement. Since 2013, planning authorities are no longer permitted to vary the standard three-year condition using this method.

Some applicants try to submit a section 73 application that tweaks other conditions—such as layout or materials—in the hope of securing a new permission with a fresh time limit. While this can occasionally reset the clock, it is a risky approach and not guaranteed to work. Local authorities are increasingly cautious about attempts to bypass the time restriction.

What If Permission Has Already Expired?

If the three-year period has already passed and no lawful start was made, the planning permission is no longer valid. The only route forward is to submit a new full planning application and go through the process again. This application will be assessed against current planning policies, which may have changed since the original approval. For example, sustainability standards, biodiversity requirements, or local design codes may now apply.

In some cases, the site context may also have changed. Neighbouring developments, road layouts, or changes to flood risk mapping can all affect how a new application is judged. Even if your previous proposal was approved, a resubmission does not guarantee the same result.

Strategic Tips for Developers and Homeowners

The best way to extend the life of a planning permission is to act early. If you know that the project will be delayed, aim to make a valid material start well before the three-year expiry. This means instructing contractors, submitting pre-commencement details, and documenting your progress.

Keep detailed records, including photos, site logs, and dated correspondence. These can help prove that the permission was lawfully implemented if any questions arise in the future. If needed, you can apply for a lawful development certificate to confirm that the permission remains extant.

If a full start is not feasible, explore submitting a fresh planning application in good time. Consider any updates to policy and engage with the local planning authority early, especially if the area is subject to design codes, conservation constraints, or new development plans.

Real-World Example

A developer in Hampshire secured permission in 2021 for six terraced homes on a brownfield site. Due to economic uncertainty, construction was delayed. By mid-2024, no work had begun and the team faced losing their permission. To preserve it, the developer instructed groundworkers to excavate foundations on one of the plots. All pre-commencement conditions had been discharged two weeks earlier. The work was completed and documented with photos and signed reports. The planning officer confirmed that the permission had been lawfully implemented, allowing the rest of the site to be built out over time.

Conclusion

There is no longer a direct way to extend planning permission beyond three years once granted. If you want to keep your approval alive, you must either begin lawful development before it expires or reapply with a fresh planning submission. Acting early, discharging conditions properly, and keeping accurate records are essential to protecting your permission. With careful planning and professional support, you can avoid costly setbacks and keep your project moving forward.