Here’s a brief summary of the different commercial usage types:

Use Classes Use / Description of development Permitted change
A1 Shops Shops, retail warehouses, post offices, ticket and travel agents, hairdressers, funeral directors and undertakers, domestic hire shops, dry cleaners, sandwich bars (sandwiches or other cold as a shop and single flat and vice versa food purchased and consumed off the premises), internet and cyber cafes. No permitted change except to mixed use as a shop and single flat and vice versa
A2 Financial and professional services Financial services (banks, building societies and bureau de change), professional services (excluding health of medical services), other services – betting shops. Principally where services are provided to visiting members of the public. A1(where there is a ground floor display window)
A3 Restaurants and cafes Restaurants, snack bars and cafes. Use of for the sale of food for consumption on the premises. A1 or A2
A4 Drinking establishments Use as a public house, wine bar or other drinking establishment. The primary purpose is the sale and consumption of alcoholic drink on the premises (excluding nightclubs). A1, A2 or A3
A5 Hot food takeaway Use of the sale of hot food for consumption off the premises. A1, A2 or A3
B1 Business Offices - other than those classified within A2 (financial and professional services). Research and development such as laboratories and studios. Light industry appropriate in a residential area. B8 (where no more than 235sqm)
B2 General industrial General industry (other than classified within B1) - excluding incineration purposes, chemical treatment or landfill or hazardous waste. The former ‘special industrial’ use classes (B3-B7), are now classified under B2. B1 (unlimited) or B8 (where no more than 235sqm)
B8 Storage or distribution Storage or distribution centers, including open air storage. B1 (where no more than 235sqm)
C1 Hotels Hotels, boarding houses and guest houses where no significant provision of care is provided (excludes hostels) No permitted change
C2 Residential institutions Hospitals, nursing homes, residential schools and training centers. Use for the provision of residential accommodation and care to people in need. No permitted change
C2A Secure residential institution Use of the provision of secure residential accommodation, including use as a prison, young offenders institution, detention centre, secure training centre, custody centre, short term holding centre, secure hospital, secure local authority accommodation or use as a military barracks No permitted change
C3 Dwelling houses Dwellings for individuals, families or not for more than six people living together as a single household includes up to six people living together within a supported housing scheme. No permitted change
C4 Houses in multiple occupation Small shared dwelling houses occupied by between three and six unrelated individuals as their only or main residence, who share basic amenities such as a kitchen or bathroom. C3
D1 Non-residential institutions Medical and health services, crèche, day nursery, day centers, museums, public halls, libraries, art galleries exhibition halls, non-residential education and training centers, places of worship, church halls and law courts No permitted change
D2 Assembly and leisure Cinemas, concert halls, sports halls, swimming baths, skating rinks, gymnasiums, bingo halls, other indoor and outdoor sports and leisure uses, not involving motorised vehicles or firearms. No permitted change
Sui generic There are many uses that are not specifically categorised by the four main use classes. These are(except casinos: categorised as ‘sui generis’. These include petrol stations, casinos, retail warehouse clubs, amusement arcades, launderettes, taxi or vehicle hire, selling and displaying motor vehicles, nightclubs, theatres, hostels (providing no significant level of care), builders yards, scrap yards and houses in multiple occupation. No permitted change (except casinos: permitted change from sui generic to D2)

The above is intended as a general guide only. Reference must be made in the final instance to the Town and Country Planning Act 1990 as amended, the Use Classes Order 1987 as amended, and the General Development Order 1988 as amended.