Certificates of lawfulness, and the rule that changed in 2024
Why these appear in your search results, whether they are work, and the four-year rule that is now ten.
Applies to England. Facts last checked 4 Aug 2026. Guides describe England; other UK nations run separate planning systems.
Two different certificates
A certificate of lawfulness for a proposed use or development asks the council to confirm that work someone intends to do needs no permission. A certificate for an existing use asks it to confirm that work already done has become lawful through the passage of time.
They look similar in a search result and mean opposite things. The first is somebody about to build. The second is somebody regularising something built years ago, often to sell the house.
The rule that changed
Enforcement against unauthorised building work used to become time-barred after four years. Section 115 of the Levelling-up and Regeneration Act 2023 changed that to ten years in England, with effect from 25 April 2024.
The four-year period still applies where the work was substantially complete before that date. So in practice both rules are live, and which one applies depends on when the building went up. This is England only — the four-year rule continues in Wales.
What it means for finding work
A proposed-use certificate is a genuine early signal: the owner has taken advice, believes the work is permitted development, and intends to proceed. Nobody pays for one idly.
An existing-use certificate usually is not work — it is paperwork on something already standing. Tradecue classifies the two separately for that reason, so you can filter the second kind out of the feed rather than reading through them one at a time.
Sources
General explanation, not legal or planning advice. Anything that turns on the detail of a particular site is worth a free phone call to the council’s planning department. Something here wrong or out of date? Tell us.