The 90-day rule caps entire-home short lets anywhere in Greater London at 90 nights per calendar year, under section 25 of the Greater London Council (General Powers) Act 1973. Letting a whole dwelling as temporary sleeping accommodation beyond 90 nights is a material change of use requiring planning permission, and doing it without permission is an offence carrying fines of up to £20,000. The cap was created by section 44 of the Deregulation Act 2015, which legalised short letting up to that limit.
The detail
The detail decides whether it binds you. It counts nights let, not bookings, and runs on the calendar year, resetting on 1 January. It applies only to lets of the whole property — renting a room while you are in residence does not count towards the 90 and is unrestricted. Lets of more than 90 consecutive nights to the same occupier are a tenancy, not temporary sleeping accommodation, and fall outside the rule entirely, which is why mid-let and corporate relocation lets are the standard legal route around it. The cap covers all 32 boroughs and the City of London, and nowhere else in England.
Airbnb applies an automatic 90-night limit per listing in Greater London, but the cap attaches to the property, not the listing. Splitting a property across two Airbnb listings, or running Airbnb alongside Booking.com and Vrbo, does not lawfully extend it — and it is precisely the pattern that borough enforcement teams look for. Westminster and Kensington & Chelsea both run dedicated short-let enforcement, working from platform data, council tax records and neighbour complaints.
The commercial consequence is the part that gets skipped. Ninety nights at a central London rate of £150-£190 grosses £13,500-£17,100 before any costs. A one-bedroom flat in zone 2 letting at £1,700 a month grosses £20,400 on an assured shorthold tenancy with a fraction of the work. For most central London properties, complying with the 90-day rule makes short letting the worse business — which is the honest answer to why so many operators do not comply.
The numbers that matter
Where this stops holding
The 90-day rule is a planning rule, so it binds regardless of which platform you use or whether you use one at all — which catches out hosts who move to direct booking believing the limit is an Airbnb policy. It is also not the only constraint on a London flat: most leasehold leases separately prohibit lets under six months, and a freeholder can enforce that clause whether or not you stay under 90 nights. Conversely, the rule does not apply one mile outside the Greater London boundary, which is why the yield map changes abruptly at the M25.
Sources
Get this answered for your address
A HostPal Invest report runs the real occupancy, nightly rate, RevPAR, regulation risk and a buy / wait / avoid verdict for one specific property or drawn area, in any of 117 markets — not a national average. Street-Level reports from £29.