Planning Enforcement in London: What Happens If You Build Without Permission?
Building without planning permission — or in breach of conditions attached to a planning permission — is a planning enforcement matter in London. Understanding how enforcement works helps you assess risk, act quickly if you inherit a problem, and avoid making costly mistakes.
Is It Automatically Illegal to Build Without Permission?
No — not all development requires planning permission. Permitted development rights allow many common works (rear extensions to PD limits, loft conversions without dormers exceeding the permitted size, change of use between certain uses) without a formal planning application. However, where planning permission is required and not obtained, the development is unlawful and subject to enforcement action.
What Triggers Enforcement Action?
Planning authorities investigate alleged breaches of planning control following complaints from neighbours, observations by planning officers, or proactive monitoring. In London, the most common triggers for residential enforcement complaints are:
- Extensions built larger than permitted development limits
- Extensions built in conservation areas without permission
- Unauthorised changes of use (residential to HMO, commercial to residential)
- Outbuildings built in breach of PD limits
- Works carried out in breach of planning conditions
The Enforcement Process
Investigation: The council investigates the alleged breach — a planning enforcement officer visits and assesses what has been built or done.
Breach of condition notice / Planning Contravention Notice: The council may issue a Planning Contravention Notice requiring you to provide information about the development.
Enforcement Notice: If the council decides to take formal action, they issue an Enforcement Notice. This specifies what has been done, why it breaches planning control, and what must be done — typically requiring the unauthorised work to be removed or altered, or a retrospective application to be made within a set time period.
Appeals: You can appeal an Enforcement Notice to the Planning Inspectorate within the time limit specified on the notice (typically 28 days). An appeal suspends the notice while it is being considered.
Retrospective planning application: In many cases, the best response to an Enforcement Notice is to submit a retrospective planning application. If the council would actually grant permission for what has been built, it is generally better to regularise the position through planning permission than to demolish or alter.
Prosecution: Where a person fails to comply with an Enforcement Notice after it takes effect, they can be prosecuted in the magistrates court and fined.
Time Limits
There are time limits on enforcement action:
- Four years: For operations (building works) — the council can only take enforcement action within 4 years of the breach
- Ten years: For change of use — the council has 10 years from the date of the change of use
After these time limits expire, the development becomes immune from enforcement. It can then be regularised with a Certificate of Lawfulness of Existing Use or Development (CLEUD).
Practical Implications for Buyers and Sellers
If you are buying a property with works that may lack planning permission, your solicitor will identify this in searches. Options include:
- Obtaining retrospective planning permission before exchange
- Obtaining a Certificate of Lawfulness (if time limits have passed)
- Indemnity insurance (insures against enforcement action — not always appropriate)
RCB Design & Build
RCB Design & Build advises clients on planning compliance and PD rules before any work starts — ensuring projects are properly authorised and clients understand their position.