| Classic Racing Motorcycle Club Limited | Norwich | 1987 |
| Classic Rallies Limited | Reading | 2023 |
| Classic Rally Limited | Deeside | 2012 |
| Classic Road Trips Ltd | Wallingford | 2012 |
| Classic Rugby Limited | Neath | 2019 |
| Classic Saloon Car Club (Great Britain) Limited | Oxford | 1992 |
| Classic Sports Car Club Limited | Corsham | 2003 |
| Classic Stitch Limited | Wakefield West Yorkshire | 1996 |
| Classic Stockcars Ltd | Milton Keynes | 2023 |
| Classical Art London Ltd | London | 2020 |
| Classical Ballet Centre (Surrey) Limited | Fleet | 2006 |
| Classical Barbell Ltd | London | 2023 |
| Classical Concert Promotions Limited | London | 2010 |
| Classical DJ Ltd | London | 2026 |
| Classical Events Limited | Manchester | 2005 |
| Classical Kicks Productions Ltd | London | 2012 |
| Classical Music Licensing Ltd | Louth | 2015 |
| Classical NOT Boring Ltd | London | 2024 |
| Classical Opera | London | 2015 |
| Classical Pilates Limited | Glasgow | 2005 |
| Classical Pilates London Ltd | London | 2025 |
| Classical Spectacular Limited | London | 1991 |
| Classicalfitnesspro Ltd | North Ferriby | 2020 |
| Classically British & Co. CIC | London | 2025 |
| Classically Social Ltd | London | 2026 |
| Classicberry Limited | London | 1982 |
| Classicdressage Ltd | Warwick | 2012 |
| Classico Latino Music Limited | Cambridge | 2017 |
| Classics Gym Ltd | Liverpool | 2026 |
| Classification Productions Limited | London | 2024 |
| Classified Entertainment Limited | Palmers Green | 2013 |
| Classique Musicians for Hire Limited | Wembley | 2009 |
| Classique School of Dance Limited | Fareham | 2012 |
| Classroom Adventures Ltd | Milton Keynes | 2016 |
| Classtrend Limited | Penistone Road | 1992 |
| Classy Competitions Ltd | Newcastle Upon Tyne | 2026 |
| Classy Events Ltd | London | 2026 |
| Classy Gym Ltd | London | 2025 |
| Clatt Auld Kirk | Huntly | 1995 |
| Clatter Community Centre Limited | Caersws | 2013 |
| Claudia Caolin Dance and Entertainment CIC | Camborne | 2018 |
| Claudia Erecords Limited | Liverpool | 2016 |
| Claudia Parker Limited | London | 2013 |
| Claudia VC Limited | London | 2022 |
| Claudie's Club Limited | Birmingham | 2019 |
| Claudinc Limited | London | 2019 |
| Claughton Hall Syndicate Ltd | Carnforth | 2020 |
| Claverdon Lions Ltd | Worcester | 2023 |
| Claverdon Rugby Club Limited | Warwick | 2014 |
| Claverdon Rugby Clubhouse Limited | Warwick | 2014 |
| Clavius Films Ltd | Scarborough | 2021 |
| Claw Kingdom Leicester Ltd | Syston | 2026 |
| Claw Kingdom Nottingham Ltd | Birmingham | 2026 |
| Claxton Sports Academy Ltd | Ormskirk | 2025 |
| Claxton Thoroughbreds Limited | Newmarket | 2022 |
| Clay & Country Ltd | Shifnal | 2025 |
| Clay 10 Limited | Bromsgrove | 2011 |
| Clay and Game Limited | Melton | 2011 |
| Clay and Glaze Limited | Rochdale | 2025 |
| Clay Brow FC Juniors CIC | Skelmersdale | 2026 |
| Clay Cellars Studio Ltd | Paignton | 2025 |
| Clay Connections Ltd | Frodsham | 2023 |
| Clay Day Creations Ltd | Guildford | 2024 |
| Clay Days London Ltd | Beckenham | 2022 |
| Clay Galeria Ltd | London | 2024 |
| Clay Lane Academy Ltd | Little Eaton | 2023 |
| Clay Pigeon Kart Club Limited | Dorchester | 1983 |
| Clay Pigeon Shoot Ltd | Southend-On-Sea | 2000 |
| Clay Pigeon Shooting Association Limited | Brookwood, Woking | 1996 |
| Clay Play CIC | Glasgow | 2025 |
| Clay Productions Live Limited | London | 2023 |
| Clay Shed Limited | Bristol | 2018 |
| Clay Shots Limited | Woodford Green | 2014 |
| Clay Sports Shooting Ltd | Deeside | 2020 |
| Clay Target Shooting Academy Limited | Bury St. Edmunds | 2018 |
| Clay Target Shooting Activities Limited | Bury St. Edmunds | 2018 |
| Clay Target Shooting Associates Limited | Bury St. Edmunds | 2018 |
| Clay Workshop Ltd | Liverpool | 2024 |
| Clayantel Ltd | London | 2025 |
| Claybody Theatre | Stoke-On-Trent | 2015 |
| Claydon Cycling Club CIC | Towcester | 2021 |
| Clayfield Investments Limited | Chipping Norton | 1962 |
| Clayful Hands Limited | Hove | 2024 |
| Clayful Learning Ltd | Fivemiletown | 2026 |
| Clayground Collective Limited | London | 2007 |
| Clayment Limited | Guildford | 2002 |
| Claymore Crossfit Training Limited | Perth | 2015 |
| Claymore Health & Fitness Ltd | Tamworth | 2018 |
| Claymore Miniatures Ltd | Morpeth | 2020 |
| Clayplaycommunity Ltd | London | 2023 |
| Clays and Country Limited | Worcester | 2026 |
| Clays Away Ltd | Chippenham | 2021 |
| Clays Gym Ltd | Keswick | 2026 |
| Clayspace Studios Ltd | Margate | 2015 |
| Claystation Ltd | Bolton | 2023 |
| Claytara Limited | Edinburgh | 1995 |
| Clayton Stables Ltd | Abingdon | 2024 |
| Clayton,Son & Co.Limited | Hunslet | 1961 |
| Claytons Ground Care Limited | Wolverhampton | 2019 |
| Claywest Studio Ltd | London | 2024 |