Planning Use Classes for London Properties: What Every Homeowner Should Know

Class C3 — Dwelling House: The use class for a single dwelling occupied by a household (a single person, a family, or up to 6 people living together as a single household unit). Class C3 covers the vast majority of London houses and owner-occupied or let residential property. Within Class C3 there are three sub-categories: C3(a) — single person, couple, or family; C3(b) — up to 6 people living together with support (such as care home residents); C3(c) — up to 6 people living together as a single household who are not a family, but still function as a household. The most important point for homeowners: a property must be used as a single household's home to remain in Class C3. Subdividing a house into separate self-contained units (flats) is a material change of use that requires planning permission — even if each unit remains within Class C3 individually. Class C4 — Houses in Multiple Occupation (HMO): Small HMOs — properties occupied by 3-6 unrelated people sharing basic facilities (kitchen, bathroom) — are Class C4. Traditionally, change from C3 to C4 was permitted development (no planning permission needed). However, many London boroughs — including Hammersmith and Fulham, Islington, Southwark, Lewisham, Hackney, and others — have implemented Article 4 Directions removing this PD right, requiring planning permission for any C3→C4 change of use. Large HMOs (7 or more occupants) require planning permission in all cases — they fall outside the use classes order entirely as "sui generis." Class C5 — Short-term Let: Introduced in 2024, Class C5 covers short-term let dwellings (such as Airbnb lets exceeding 90 nights per year in London under the Deregulation Act 2015, or let outside the temporary exemption). This is a significant change — where a dwelling is used predominantly for short-term commercial letting rather than as a principal home, it may fall into Class C5 rather than C3, and a change of use planning application may be required.

Class E (Commercial, Business and Service) was introduced in September 2020, consolidating a range of previously separate commercial use classes: retail shops (formerly A1), restaurants and cafes (formerly A3 — but not pubs or takeaways), financial and professional services (formerly A2), offices and light industrial (formerly B1), health centres and gyms, and nurseries and creches. The significance of Class E for London: Within Class E, businesses can change from one type to another without planning permission. A former bank can become a restaurant, an office can become a gym, a retail shop can become a nursery — all without formal planning permission. This was designed to give town centres more flexibility to adapt to changing retail patterns. However, Class E does not include pubs (which remain Class A4, now sui generis as "drinking establishments"), hot food takeaways (formerly A5, now sui generis), or residential. Change from Class E to residential (Class C3) may be possible under permitted development in some circumstances — the commercial to residential prior approval route (Class MA of the GPDO) allows certain Class E buildings (where the Class E use has been in place for a minimum of 2 years and the building has been vacant for at least 3 months) to be converted to residential dwellings through a prior approval process rather than full planning permission. Many London boroughs have removed this PD right using Article 4 Directions for their most commercially active areas — check the specific borough before relying on Class MA.

An Article 4 Direction is a direction made by a local planning authority that removes specified permitted development rights within a defined area. Article 4 Directions are used across London for two main purposes: Protecting residential stock from HMO conversion: Multiple London boroughs have Article 4 Directions removing the C3→C4 PD right in most or all of their areas, requiring planning permission for any house to be used as an HMO. Protecting commercial premises from residential conversion: In major town centre and employment areas, Article 4 Directions remove the Class MA PD right (commercial to residential), requiring full planning permission for such changes. Before relying on any permitted development right for a change of use, always check: whether the specific borough has an Article 4 Direction in the relevant area; whether the building has any planning conditions that restrict change of use; and whether the property is in a conservation area, where additional restrictions may apply. An Article 4 Direction is searchable through the local planning authority's planning portal or by requesting a Local Land Charges search.

Understanding use classes has several direct practical implications for London property: Buying property with conversion potential: Before purchasing a house with a view to converting it into flats or an HMO, verify the current planning position — is the C3→C4 right removed by Article 4? Is flat conversion viable given the local planning authority's policies on residential subdivision? Have permitted development rights for any other intended use change been removed? This verification is essential before offers are made — discovering after exchange that the intended use change requires planning permission (which the local authority may resist) can make the transaction financially unviable. For landlords: Operating a property as an HMO above the 6-person threshold, or in a borough where C3→C4 is not permitted development, without the required planning permission creates enforcement risk. Planning enforcement for unauthorised HMO use carries a civil penalty and can be registered as a local land charge, affecting future mortgage and sale prospects. For homeowners letting on Airbnb: In London, short-term letting is restricted to 90 nights per year under the Deregulation Act 2015 without planning permission. Exceeding this threshold without permission may now also involve a change of use into Class C5, requiring retrospective planning permission. Local authorities increasingly monitor and enforce this limit.