| Clarkson's of Cheshire Limited | Birkenhead | 2013 |
| Clarkwell Ltd. | London | 2019 |
| Clarson Goff Management Limited | Gatwick | 2015 |
| Clarson Limited | Lichfield | 2025 |
| Clarus Homes Ltd | West Midlands | 2004 |
| Class Acts Promotions (Ireland) Ltd | Belfast | 1997 |
| Class One Line Marking Limited | Bonnybridge | 2012 |
| Class Properties Limited | London | 2019 |
| Class Stage Productions Ltd | London | 2007 |
| Class Teacher Services Limited | Wellingborough | 2001 |
| Classic & Vintage Limited | Orpington | 2019 |
| Classic American Sports Ltd | Hyde | 2019 |
| Classic and Collectable Club Insurances Limited | Carrickfergus | 1998 |
| Classic and Military Models Ltd | Swanage | 2015 |
| Classic Bulbs Limited | Malvern | 2024 |
| Classic Car Auctions Ltd | Ashorne | 2014 |
| Classic Cars for Sale Limited | Warwick | 2026 |
| Classic Ceilings Limited | Co Derry | 2001 |
| Classic Claret Limited | Macclesfield | 2007 |
| Classic Coaching Consultants Limited | Norwich | 2020 |
| Classic Connection Limited | Brockenhurst | 1994 |
| Classic Eggs Limited | Taunton | 1999 |
| Classic Food Supplies Limited | London | 1992 |
| Classic Football Shirts Limited | Hyde | 2015 |
| Classic Football Shops Limited | Hyde | 2018 |
| Classic Fuel Solutions Ltd | Poole | 2022 |
| Classic Gold Limited | London | 1999 |
| Classic London Services Limited | Waterlooville | 2013 |
| Classic Mini Spares Limited | Potters Bar | 1999 |
| Classic Motor Finance Limited | Maidstone | 2015 |
| Classic Oils Limited | Bicester | 2022 |
| Classic Properties ( Southport ) Ltd | Richmond | 2023 |
| Classic Racing Drivers Club Limited | Northampton | 2010 |
| Classic Revive and Drive Ltd | Brighton | 2024 |
| Classic Rewinds Limited | Nottingham | 1963 |
| Classic Security Ltd | London | 2019 |
| Classic Shoe Repairs Limited | London | 2013 |
| Classic Tractor Workshop Ltd | Leigh | 2025 |
| Classic Valeting Limited | Hertford | 2009 |
| Classic Voyages Limited | Huntingdon | 2010 |
| Classic Wings and Wheels Limited | Norwich | 2010 |
| Classical Beauty Ltd | Kenilworth | 2017 |
| Classical Interludes Ltd | Welshpool | 2023 |
| Classical Toilet Hire Ltd | Bury St. Edmunds | 2018 |
| Classicalguitarmart Limited | St. Leonards-On-Sea | 2014 |
| Classicsoft Corporation Limited | London | 2015 |
| Classicworx Limited | Rugby | 2019 |
| Classiflora Limited | Waltham Abbey | 2025 |
| Classroom Table Company Limited | Plymouth | 2021 |
| Classtech Solutions Limited | Horsham | 2012 |
| Classy Agreements Ltd | Norwich | 2022 |
| Classy Entertainment Ltd | Doncaster | 2015 |
| Claud Ltd | London | 2024 |
| Claudette Cheryl Griffith Limited | Mitcham | 2025 |
| Claudette Elaine Parkins Limited | Enfield | 2023 |
| Claudia Fabiola Roubaty Ltd | London | 2024 |
| Claudia Knox Limited | Maidstone | 2023 |
| Claudia Nielsen Consultancy Limited | Woking | 2022 |
| Claudia Rosa Ltd | Hailsham | 2012 |
| Claudius Debt Purchase Limited | Grantham | 2026 |
| Claudius Vertesi Ltd. | Corby | 2017 |
| Claverton Developments Limited | Hayes | 2020 |
| Clavie Developments Limited | Moray | 1990 |
| Claw Commercial Ltd | Swanage | 2014 |
| Claw Nuclear Services Ltd | Weybridge | 2014 |
| Claw Remediation Services Ltd | Weybridge | 2014 |
| Clay 30 Limited | Leigh On Sea | 2012 |
| Clay and Concrete Construction Materials Limited | Walsall | 1984 |
| Clay Bashing Limited | Ilford | 2024 |
| Clay Colliery Company Limited | London | 1987 |
| Clay Incorporated Ltd | Belfast | 2019 |
| Clay Publications Limited | Oldbury | 2023 |
| Claycourt Limited | Swindon | 2016 |
| Claydon Hardy Associates Limited | Barnsley | 2017 |
| Clayfield House Management Limited | Berwick-Upon-Tweed | 2004 |
| Claylands Hire Limited | Fareham | 2002 |
| Claymold Ltd | London | 2026 |
| Claymon Limited | Blackpool | 2018 |
| Claymore Industrial Investment Company Limited | Ely | 2016 |
| Clays Butchers Ltd | Leicester | 2012 |
| Claysco Limited | Belfast | 2025 |
| Clayton Contract Furnishings Limited | Accrington | 2011 |
| Clayton Holiday Lettings Ltd | Warrington | 2023 |
| Clayton's Upholstery Limited | Lincoln | 1984 |
| CLB 44 Limited | Warrenpoint | 2018 |
| Clball Electrical Co., Limited | London | 2023 |
| CLC the Lord Chief Justice MR N a Johnson MBA QA Limited | Sutton Coldfield | 2020 |
| CLC the Lord Circuit Judge MR N a Johnson QA Ltd | Sutton Coldfield | 2020 |
| CLC World Limited | London | 2012 |
| CLC World Travel Limited | London | 2013 |
| CLD Systems Limited | Sandbach | 2022 |
| CLE EN Main Corp., Ltd | Cambridge | 2014 |
| CLE Management Services Ltd | Coventry | 2018 |
| Cleadon Property Development Ltd | East Boldon | 2020 |
| Clean Air 24SEVEN Ltd | Saffron Walden | 2011 |
| Clean Air in Cities Ltd | Marlow | 2010 |
| Clean Air London Limited | Marlow | 2022 |
| Clean and Gone Limited | London | 2014 |
| Clean Arya Ltd | Aylesbury | 2024 |
| Clean Code Investments Limited | London | 2025 |