| Clare Mackintosh Ltd | Bala | 2013 |
| Clare Mcquillan Limited | London | 2021 |
| Clare's Canines Mortlake Limited | Mortlake | 2022 |
| Clare's Space Limited | Knutsford | 2019 |
| Clarehaven Ltd | Newmarket | 2017 |
| Claremont 56 Limited | Margate | 2013 |
| Claremont Lawn Tennis Club (1932) Limited | Altrincham | 1932 |
| Claremont Stratagem Ltd | Mansfield | 2025 |
| Claremont Youth Project C.I.C. | Manchester | 2020 |
| Clarence & Avondale Padel Club Ltd | Edinburgh | 2025 |
| Clarence Holdings Limited | Ashton Under Lyne | 2003 |
| Clarence Marina Limited | Nottingham | 2006 |
| Clarence Park Health Suite Limited | Droitwich | 2015 |
| Clarence Snooker Club Limited | Beverley | 2001 |
| Clarendell Limited | 56 Dingwall Road | 1986 |
| Clarendon Development Association Ltd | Belfast | 2022 |
| Clarendon Park Shoot Club Limited | Salisbury | 2011 |
| Clarets Consortium Ltd | Sittingbourne | 2023 |
| Clare’S Daily Edit Ltd | Banbury | 2025 |
| Clargo Outdoors Limited | Abingdon | 2026 |
| Clarice Fitness Ltd | Anerley | 2021 |
| Clarice Price Thomas Ltd | London | 2017 |
| Clarin Oyster Maritime Limited | Dorset | 2008 |
| Clarinet and Saxophone Society of Great Britain | Dartford | 1995 |
| Clarion Music Ltd. | Haslemere | 2015 |
| Claris Ltd | Llanarth | 2008 |
| Clarissa's Clart Ltd | London | 2019 |
| Claristar Ltd | Boston | 2021 |
| Clarity 11 Group Limited | St. Albans | 2015 |
| Clarity Audio Visual Ltd | Glasgow | 2019 |
| Clarity Audio Visual Solutions Limited | Knaresborough | 2018 |
| Clarity Co Management Limited | Aylesbury | 2025 |
| Clarity Comps Limited | Battle | 2023 |
| Clarity Entertainment Limited | Bolton | 2017 |
| Clarity Gained Ltd | Coventry | 2018 |
| Clark Baker & SON Limited | Loughton | 2005 |
| Clark Elite Performance Ltd | Leicester | 2025 |
| Clark Racing (Northern) Limited | Epping | 1990 |
| Clark Racing Limited | Maidstone | 2020 |
| Clark's Leisure & Catering Limited | Lytham St Annes | 2002 |
| Clark-Nicol Limited | Swaffham | 2015 |
| Clarke Artists Limited | Birmingham | 2010 |
| Clarke Environmental Limited | Staffordshire | 2003 |
| Clarke Fitness Ltd | Armagh | 2014 |
| Clarke Gonzalez Limited | London | 1998 |
| Clarke Heafield Limited | Barnstaple | 2014 |
| Clarke Warner Ltd | Birmingham | 2017 |
| Clarke's Funfair Limited | Glasgow | 2025 |
| Clarkey Entertainment Limited | London | 2024 |
| Clarke’S Construction Ltd | London | 2013 |
| Clarksfield & Glodwick (C&G) Community Sports Club CIC | Oldham | 2023 |
| Clarkson Bell Ltd | London | 2022 |
| Clarkson Events Collabs Limited | Newcastle Upon Tyne | 2021 |
| Clarkson Leisure Limited | Newcastle Upon Tyne | 2014 |
| Clark’S Film Animals Ltd | High Wycombe | 2025 |
| Clarmov Ltd | Maghera | 2010 |
| Claro Media Limited | Surrey | 2002 |
| Clarus Sports Management Ltd | Newport | 2025 |
| Clash of the Crooners Ltd | Colne | 2024 |
| Clashfit Training Ltd | Redhill | 2020 |
| Class 1 Entertainments Limited | Derby | 2002 |
| Class 20 Locomotive Company | Leighton Buzzard | 2026 |
| Class 33/1 Preservation Company Limited | Willenhall | 1997 |
| Class 56 Locomotives Limited | Sutton Coldfield | 2005 |
| Class ACT Theatre Group Ltd | Strabane | 2020 |
| Class ACT Theatrix Limited | Birmingham | 2017 |
| Class Classes Ltd | Wigan | 2019 |
| Class Events and Workshops Ltd | Harpenden | 2021 |
| Class Fit Gym Ltd | Liversedge | 2024 |
| Class Hockey Limited | Cambridge | 2018 |
| Class of 92 Limited | Manchester | 2012 |
| Class PT Ltd | Batley | 2026 |
| Class Riverside Ltd | Grimsby | 2018 |
| Class Yachting Ltd | London | 2024 |
| Classes With Catherine Limited | North Shields | 2023 |
| Classfit Ltd | Ashington | 2015 |
| Classfree Limited | Deeside | 1992 |
| Classic Album Sundays Limited | London | 2014 |
| Classic Albums Live UK Ltd | London | 2025 |
| Classic and Historic Motor Club Limited | Cheddar | 1980 |
| Classic and Modern Motorsport Club (2021) Limited | Trowbridge | 2021 |
| Classic Antique Fairs Ltd | Redhill | 2023 |
| Classic Autotest Motorclub Ltd | Ballynahinch | 2014 |
| Classic B & I Rugby Ltd | Weston-Super-Mare | 2024 |
| Classic Bike Trackdays Limited | Bath | 2010 |
| Classic Bindings Limited | Moreton-In-Marsh | 1996 |
| Classic Car Racing Limited | Buckinghamshire | 1997 |
| Classic Carp Limited | Grantham | 2014 |
| Classic Casino Entertainments Limited | West Midlands | 2001 |
| Classic Casino Limited | West Midlands | 2001 |
| Classic Channel Regatta Limited | Dartmouth | 2014 |
| Classic Concerts Trust | Surrey | 1986 |
| Classic Fitness Ltd | Warminster | 2021 |
| Classic Home Cinema Ltd | Cleethorpes | 2026 |
| Classic Lions Limited | Neath | 2019 |
| Classic Memories Ltd | Newcastle Under Lyme | 2025 |
| Classic Motor and Music Ltd | Herne Bay | 2018 |
| Classic Physiques Gym Ltd | Walsall | 2018 |
| Classic Presentations Limited | London | 1960 |
| Classic Racing Egts Ltd | Dunmow | 2014 |