What the 90-Day Rule Actually Is

The rule originates from the Deregulation Act 2015, which amended section 25 of the Greater London Council (General Powers) Act 1973. Before 2015, any short-term letting of a residential property in London (defined as stays of fewer than 90 consecutive nights) technically required planning permission. The 2015 Act relaxed this by creating an automatic exemption: residential properties could be used as temporary sleeping accommodation for up to 90 nights per calendar year without a planning application, provided two conditions were met.

The conditions: the cumulative total must not exceed 90 nights between 1 January and 31 December, and at least one person providing the accommodation must be liable to pay council tax at the property. That second condition is the one most landlords miss as it was designed to allow homeowners to let their own residence while on holiday or away for work. It was not designed for commercial buy-to-let portfolios, though in practice the condition is met by the managing agent’s operational structure in many professional arrangements.

The 90-night limit applies to the property, not the owner. If you list on Airbnb for 50 nights and Booking.com for 40 nights, you have used all 90. The platforms do not share data with each other. Tracking is the host’s legal responsibility.

What Counts Towards the 90 Days (and What Doesn’t)

Counts: every night the entire property is occupied by a paying guest on a stay of fewer than 90 consecutive nights. Whether booked through a platform, through an agent, or arranged privately, each occupied night adds to the annual total.

Does not count: letting a spare room while the host remains in residence. The 90-day rule applies only to entire-property lets where the host is absent. If you rent a room in your own home and continue to live there, the cap does not apply. You can host room-only guests year-round.

Does not count: medium-term and long-term lets. A tenancy where a single guest or household occupies the property for 90 consecutive nights or more is not classified as temporary sleeping accommodation. It is a residential occupation. A three-month corporate let, a six-month relocation tenancy, or any continuous single-household stay of 90+ nights sits entirely outside the rule. This distinction is the legal foundation of the hybrid model (short-term lets for 90 nights, medium-term lets for the remainder of the year).

Grey area: stays of 30-89 nights booked through short-let platforms. These are technically temporary sleeping accommodation if occupied by a different person for fewer than 90 consecutive nights. In practice, stays of this length are often treated as residential by boroughs, particularly where the guest is using the property as a primary residence (corporate relocation, academic placement). But the legal position depends on the nature of the occupation, not the booking channel.

What Happens If You Exceed 90 Days

Three things, in escalating order of severity.

Platform auto-blocks. Airbnb automatically deactivates entire-home listings in Greater London once the property reaches 90 booked nights in a calendar year. The listing remains visible but cannot accept further bookings until the next January. Booking.com and other platforms have announced similar mechanisms, though enforcement varies. If you list across multiple platforms, none of them will know your combined total. That gap is your compliance risk.

Council enforcement. Local planning authorities can issue enforcement notices for breach of planning control. Using a residential property as temporary sleeping accommodation beyond 90 nights without planning permission constitutes a material change of use. Boroughs including Westminster, Kensington and Chelsea, and Camden have been increasingly active in monitoring short-let activity, using platform data, noise complaints, and neighbour reports as triggers.

Financial penalties. Fines for breaching the 90-day rule can reach £20,000 per offence. In addition to fines, a council can require the owner to cease short-let use entirely and may refuse any future planning application for the property. The reputational and operational cost of enforcement action extends well beyond the fine itself.

Enforcement has accelerated since 2017, when Airbnb agreed to share booking data with London councils on request. The introduction of a national short-term let registration scheme (targeted for 2026, with each property receiving a unique registration number displayed on all listings) will give councils substantially more visibility. Landlords operating above the cap without planning permission should assume they will be identified.

How to Legally Exceed 90 Days

Two routes. One involves the council. The other doesn’t.

Route 1: Apply for Planning Permission

A property owner can apply for planning permission for a change of use from residential (Class C3) to short-term let use. The application is submitted to the local planning authority through the Planning Portal. The statutory fee for a change-of-use application in England is £586 (from April 2025).

The fee is modest. The outcome is not guaranteed. Boroughs in Prime Central London (particularly Westminster, RBKC, and Camden) have been reluctant to grant permission for full commercial short-let use in residential buildings. Grounds for refusal typically include loss of residential housing stock, amenity impact on neighbours, and conflict with conservation area policies.

That said, permission is granted in some circumstances, particularly where the property is in a building already operating partly as serviced accommodation, where the applicant can demonstrate minimal neighbour impact, or where the property has previously been used commercially. A well-prepared application with supporting evidence (management plan, noise mitigation measures, compliance documentation) materially improves the odds.

If granted, planning permission removes the 90-night cap entirely. The property can operate as a short-term let year-round. The income differential between a hybrid model capped at 90 STR nights and a fully permitted year-round operation is substantial, often exceeding 200% of the equivalent long-let return.

Route 2: Pivot to Medium-Term Lets for the Remaining 275 Nights

No planning permission required. No council application. No fee.

Medium-term lets (stays of 90+ consecutive nights by a single household) are classified as residential occupation, not temporary sleeping accommodation. They fall outside the 90-day rule entirely. A property can operate as a short-term let for 90 nights during peak season (typically April-September) and then transition to medium-term corporate lets for the remainder of the year without breaching any planning restriction.

This is the hybrid model. It is the approach used by every serious professional operator in London. The 90 nights are deployed during the highest-rate period of the year. The remaining calendar is filled with furnished lets to corporate relocatees, embassy secondees, project-based professionals, and international families, all of whom pay above long-let market rates for furnished, flexible accommodation in prime locations.

The demand pipeline for medium-term furnished lets in Knightsbridge, Mayfair, and Belgravia runs year-round. Corporate relocation agencies, diplomatic housing offices, and private banks all place tenants into this segment. The supply of professionally managed, hotel-grade furnished stock at this tenure length is limited, which supports rate premiums significantly above the long-let equivalent.

How Professional Management Solves This

The 90-day rule is not a problem to be solved. It is a scheduling constraint to be managed.

For a self-managing landlord, compliance requires tracking booked nights across every platform, switching listing strategies at the right moment in the calendar, re-pricing for medium-term demand, vetting a different category of guest, and managing the operational transition between short stays and longer tenancies. Most landlords who attempt this without professional infrastructure either breach the cap unknowingly or leave significant income on the table during the medium-term period.

Under a professional concierge management model, this is handled as a core operational function. The booking calendar is structured from day one around the 90-night allocation. Short-let nights are concentrated in the highest-yield window. Medium-term bookings are sourced through corporate channels, relocation agencies, and direct relationships. The transition between letting modes is seamless: same property standard, same management team, same reporting.

Planning permission applications, where pursued, are prepared and funded by the management company. Compliance monitoring (night tracking, platform management, council correspondence) is absorbed within the management fee. The owner’s involvement is limited to reviewing the monthly income statement.

Belmont handles 90-day compliance as part of our standard management service, including planning permission applications at our cost, not yours. Every property receives a structured booking calendar, full night tracking, and a blended short-term and medium-term strategy designed to maximise annual yield within the law. Get a free valuation →

The Belmont Collection is a premium concierge short-let management company operating exclusively in Prime Central London (Knightsbridge, Mayfair, Belgravia, and Kensington & Chelsea). This article is for general information only and does not constitute legal advice. Property owners should consult a planning specialist for property-specific guidance.