A total of 2,712 properties under Westminster City Council are currently being investigated for unlawful short-term letting as of 30th March 2026, according to new data.
It comes ahead of the launch of a new registration scheme for short-term lets, intended to help better police the sector.
Last year, Westminster City Council opened 499 short-term letting investigations for suspected breach of the 90-night rule, under which landlords and property owners in London can legally rent their property as a short-term let for a maximum of 90 nights within a calendar year. Beyond this, they need to request planning approval from their local council.
In the same period, notices were issued to 22 properties, with a further 36 in draft. It compares to 469 new short-term letting investigations opened and two properties served notice in 2024.
The 90-day rule
The figures have been collated by the Property Buying Company after it sent Freedom of Information Requests to local authorities in London to discover the number of recorded properties in the area that were in breach of the 90-night rule.
The 90-day rule was introduced to protect Londoners’ homes and reduce issues that can be caused by short-term lets, such as noise disturbance and abandoned rubbish, that can impact such property investments.
The figures show that Tower Hamlets Borough Council investigated 24 properties in 2025, of which eight were found to be in breach of the rule. The previous year, they investigated 35 properties and found three to be in breach. Meanwhile, Hounslow Borough Council recorded ten properties in breach of the 90-day rule in 2025.
Short-term let property register
Discussions for a new short-term let property register are already underway, which will help provide clarity for property investors in the sector, with a launch date expected to be announced this year.
It’s yet to be decided whether the register will be introduced across England simultaneously. Secondary legislation is set to go through parliament with details of how the scheme will work, but it’s hoped that tracking the number of nights a property is used for will help councils prove a breach and enable them to take enforcement action.
Jonny Christie, co-founder of The Property Buying Company, said: “Losing a vast number of homes to short-term lets is a significant problem nationally and particularly in London. It’s encouraging to see that discussions are in place to take steps to tackle the issue with a short-term let property register.
“If your property is registered as a residential home, where council tax applies, you can host short-term lets for up to 90 nights. If you exceed 90 nights, you must contact your local council to apply for planning permission to change your property’s use to a holiday rental or serviced apartment.”
