| Claddex Ltd | Rugby | 1995 |
| Clade Biosciences Ltd | Macclesfield | 2025 |
| Clade Engineering Systems Group Ltd | Bristol | 2014 |
| Clade Engineering Systems Ltd | Bristol | 2008 |
| Clade Ltd | Bristol | 2018 |
| Cladini Studio Ltd | Sheffield | 2025 |
| Cladinstone Limited | Henley-In-Arden | 2021 |
| Cladmate Facade Systems Ltd. | London | 2019 |
| Claense Ltd | London | 2017 |
| Clairair Limited | London | 2006 |
| Claire Broad Design Limited | Lichfield | 2025 |
| Claire English Ltd | Birmingham | 2010 |
| Claire Giles Ltd | Salford | 2012 |
| Claire Howard Jewellery Ltd | Fakenham | 2025 |
| Claire International Limited | Co Durham | 1986 |
| Claire O Connor Ltd | London | 2025 |
| Claire Pure Trading Limited | Beckenham | 2025 |
| Claire Tyler Couture Limited | Bognor Regis | 2018 |
| Claire's Handmade Limited | Wigton | 2010 |
| Claire-Estelle Ltd | Southampton | 2024 |
| Clairemont Electronics Limited | Glasgow | 1995 |
| Claires Artistic Licence Ltd | Harrogate | 2025 |
| Claire’S Kooky Cakes Ltd | Kilmarnock | 2022 |
| Clairglow Heating Limited | Borough Green | 1976 |
| Clak Parts Ltd | Dagenham | 2017 |
| Clam's Handmade Cakes Limited | Ebbw Vale | 2015 |
| Clamason Industries Limited | Road, Kingswinford | 1946 |
| Clamcleats Limited | Herts. | 1965 |
| Clamp Golf Limited | Barnsley | 2022 |
| Clampit Ltd | London | 2026 |
| Clan Camper Trailers Ltd | Carluke | 2020 |
| Clan House Promotions Limited | Edinburgh | 2017 |
| Clan Innovations Ltd | Leicester | 2012 |
| Clan Mcpipe Ltd | Denny | 2025 |
| Clan Tackle Ltd | Glasgow | 2025 |
| Clandeboye Yoghurt Ltd | Bangor | 2019 |
| Clanfield Systems Limited | Shoreham-By-Sea | 1995 |
| Clanmill Limited | Glasgow | 1994 |
| Clannos AI Ltd | Irvine | 2025 |
| Clannsports Ltd | Glasgow | 2025 |
| Clanpress (King's Lynn) Limited | King'S Lynn | 1975 |
| Clanrye Electrical Supplies Limited | Newry | 1988 |
| Clansman Dynamics Limited | Park, East Kilbride | 1993 |
| Clantect Limited | Southampton | 2016 |
| Claparo Innovations Limited | Cheltenham | 2019 |
| Clapham & Woolley Limited | Keighley | 2002 |
| Clapham Agricultural Engineering Ltd | Halifax | 2019 |
| Claphamflower Limited | 94A Wycliffe Road | 2016 |
| Clappersgate Limited | Chelmsford | 2021 |
| Clappp Limited | London | 2019 |
| Clar Furniture Limited | Skegness | 2021 |
| Clar Holdings Ltd | Wolverhampton | 2009 |
| Clara Bowe Ltd | Ipswich | 2015 |
| Clara CHU Ltd | London | 2022 |
| Clara Energy Ltd | Cambridge | 2015 |
| Clara Jane Ltd | Ipswich | 2026 |
| Clara PAR Ltd | Wolverhampton | 2022 |
| Clara REY Limited | Banchory | 2017 |
| Clara Rose Limited | London | 2021 |
| Clara Solutions Limited | Newcastle Upon Tyne | 2019 |
| Claraalexanderuk Ltd | Chester | 2018 |
| Clarabella Smith Interiors Ltd | Maidstone | 2022 |
| Claragh Coded Welding Ltd | Derry | 2022 |
| Claralight Ltd | Gravesend | 2019 |
| Clara’S Enchanted World Ltd | Huntingdon | 2025 |
| Clarc Commercial Fleet Services Limited | Waltham Abbey | 2025 |
| Clardon Limited | Wirral | 1993 |
| Clare Bear Ltd | Dunstable | 2026 |
| Clare Carbon Ltd | London | 2021 |
| Clare Lallow Limited | Wootton Bridge | 2003 |
| Clare Langdon Interiors Ltd | Cranbrook | 2018 |
| Clare Mullo Ltd | Burton-On-Trent | 2016 |
| Clare Paterson Ltd | Wolverhampton | 2017 |
| Clarebout Romain Ltd | Cambridge | 2025 |
| Claremont & Co London Limited | Watford | 2026 |
| Claremont Designs Ltd | Newhaven | 2012 |
| Claremont Ingredients Limited | Clevedon | 1993 |
| Claremont Sofa Designs Limited | Derby | 2014 |
| Claremont Victoria Joinery Ltd | Newcastle Upon Tyne | 2019 |
| Clarence Benjamin International Ltd | Norwich | 2022 |
| Clarence Simar Group Ltd | Hounslow | 2025 |
| Clarencebeds Ltd | Heckmondwike | 2022 |
| Clarendon Beverage Group Limited | London | 2025 |
| Clarendon Court Development Limited | London | 2002 |
| Clarendon Equestrian Limited | Hailsham | 1979 |
| Clarendon Food Company Limited(The) | Pwllheli | 1980 |
| Clarendon Glazing Ltd | Smethwick | 2022 |
| Clarendon Goods Ltd | London | 2023 |
| Clarendon Precious Metals Limited | Blackpool | 2025 |
| Clarendon Tailors & Alterations Ltd | Birmingham | 2025 |
| Clarendons Kitchens Ltd | Wrexham | 2021 |
| Clarent Precision Limited | Leighton Buzzard | 2010 |
| Claresys Limited | Abingdon | 2008 |
| Claretblew Energy Ltd | Sunderland | 2020 |
| Clarewoodworks Ltd | London | 2022 |
| Clarey's Chocolates Ltd | Broadstairs | 2024 |
| Clare’S Home Bakes Ltd | Newport | 2019 |
| Clariant OIL Services UK Ltd | Leeds | 1975 |
| Claribone Ltd | London | 2023 |
| Claridge Customs Limited | Aylesbury | 2019 |