Certificate of lawfulness for conservatory extension and outbuilding as separate dwelling

Certificates of Lawfulness Issued on 11 January 2023

four year rule enforcement

11 Shepiston Lane,

Council: London Borough of Hillingdon

The Town & Country Planning Act allows that development without planning permission becomes lawful after four years (the four year rule) or ten years (the ten year rule).

The four year rule applies to physical development (such as building an extension) or a change of use creating a new dwelling. The ten year rule applies to other changes of use (to a shop or HMO, for example) and to breaches of a planning condition.

In this recent case, our consultants helped a homeowner who had built a rear conservatory extension that did not quite meet the permitted development criteria and therefore needed planning permission, and had converted an outbuilding into a separate dwelling that had been rented out.

Both developments had taken place more than four years ago and were immune from prosecution under the four year rule. Hillingdon Council had nevertheless served planning enforcement notices, so we appealed the notices on our client’s behalf.

We can’t say this enough – never ignore a planning enforcement notice and always seek professional help from a 00chartered town planner. Enforcement notices are very serious, and simple mistakes in how you deal with them can cost you dearly. For more on enforcement, check out our dedicated enforcement page.

Enforcement appeals under the four year rule (or, indeed, the ten year rule) require a lot of supporting evidence. We worked with the client to pull together a large and detailed evidence pack and submitted it to the planning inspectorate. The evidence included historic weather data to help us date a photograph we had submitted, that showed snow on the ground! We quoted all relevant case law and submitted a persuasive supporting statement.

When the enforcement team at Hillingdon Council reviewed the evidence that we had submitted, they decided that it was robust and that there were not likely to win the appeal. They therefore withdrew from the appeal and withdrew the enforcement notices they had served. We were delighted with this success – persuading councils to withdraw enforcement notices is one of our enforcement strategies and we maintain good relationships with enforcement teams so that we are in a position to have these conversations. We wrote about the withdrawal of enforcement notices in this post.

Although the council was no longer interested in taking enforcement action against the two developments (the conservatory and the outbuilding-dwelling), the client wanted the correct documentation to show that the developments were, in fact, lawful.

So we applied to Hillingdon for certificates of lawfulness for the two developments. A certificate of lawfulness (also known as a lawful development certificate) is similar to a planning application except that it asks the council to confirm that a development is lawful. In this case, we wanted confirmation that the developments were lawful under the four year rule.

Like many planning authorities, Hillingdon is suffering from painfully high workloads and the decisions took several months. The client was patient and the case officer maintained good communication and was apologetic about the delays. We were delayed when the certificates were finally issued this week.

If you have a planning problem and would like help from our local planning consultants, contact the team by clicking on this link or emailing info@just-planning.co.uk.

Our chief executive, Martin Gaine, has a low-cost advice service on his website here and you can check out his bestselling book, ‘How to Get Planning Permission’, here. It has chapters on certificates of lawfulness the four and ten year rules and planning enforcement.

I highly recommend just-planning.co.uk for all your planning and permission needs. Martin was incredibly professional and efficient, guiding me through the process seamlessly. My permission was obtained in a timely manner and I couldn’t be happier with the outcome. Five stars!

Mr Naeem Bilal (reviewed on Facebook)

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