| Clifford Jones Timber Limited | Manchester | 1965 |
| Clifford Plant Limited | Stroud | 2003 |
| Clifford Press Limited | Coventry | 1994 |
| Clifford Springs Limited | Redditch | 2010 |
| Clifford Ward & Co. (Bridlington) Limited | Bridlington | 1973 |
| Cliffords Joinery Limited | Launceston | 2009 |
| Cliffside Windows Limited | Nottingham | 1967 |
| Clifftown Carpentry Limited | Westcliff-On-Sea | 2022 |
| Clift Controls Limited | Witham | 1978 |
| Clifton Canvas Developments Limited | Shepton Mallet | 1997 |
| Clifton Coffee Company Limited | Avonmouth | 2004 |
| Clifton Coffee Roasters Limited | Bristol | 2026 |
| Clifton Engineering (North East) Limited | Morpeth | 1993 |
| Clifton Engineering (Worcester) Limited | Worcester | 1993 |
| Clifton Engineering Services Ltd | Cheadle | 2017 |
| Clifton Packaging Group Limited | Leicester | 2002 |
| Clifton Partners Company Limited | Rochdale | 1992 |
| Clifton Racking Services Limited | Heckmondwike | 2007 |
| Clifton Rocks Contemporary Jewellery Ltd | Bristol | 2022 |
| Clifton Rubber Company Limited | St. Ives | 1973 |
| Clifton Suits Limited | Bristol | 2022 |
| Clifton Supply Limited | Stevenage | 2019 |
| Clifton Technologies Limited | Morpeth | 2019 |
| Cliftons Turf Machinery Limited | Woking | 1987 |
| Clik Dome Systems Limited | Stowmarket | 2013 |
| Clima Life Solutions Ltd | Rochdale | 2026 |
| Climabox Ltd | Bristol | 2023 |
| Climacare Group Ltd | Northampton | 2016 |
| Climacold (Midlands) Ltd | London | 2025 |
| Climafibre Ltd | London | 2022 |
| Climange Ltd | Birmingham | 2024 |
| Climarite Industrial Refrigeration Ltd | Skelmersdale | 2025 |
| Climarite Ltd | Skelmersdale | 2015 |
| Climasense Ltd | London | 2025 |
| Climate A.C.S Limited | Withington | 2013 |
| Climate and Power Limited | Grimsby | 2010 |
| Climate Autogates Limited | Saffron Walden | 2002 |
| Climate Building Services Ltd | High Wycombe | 2002 |
| Climate Care Systems Ltd | Market Harborough | 2013 |
| Climate Comfort Limited | Bournemouth | 2015 |
| Climate Components Ltd | Edenbridge | 2004 |
| Climate Control Engineering Limited | Sunbury-On-Thames | 2016 |
| Climate Control Group Limited | London | 2025 |
| Climate Dice Limited | Godalming | 2026 |
| Climate FAN Services Limited | Colchester | 2014 |
| Climate Positive Food Limited | Chichester | 2021 |
| Climate Specialist Limited | Dorchester | 2024 |
| Climate Windows Ltd | London | 2023 |
| Climatec Engineering Limited | Redcar | 2017 |
| Climatec Equipment Services Ltd. | Newent | 2019 |
| Climatec Limited | Watford | 1993 |
| Climatec Systems Limited | Ledbury | 1982 |
| Climatec Windows Limited | Leigh-On-Sea | 1993 |
| Climatecool Energy Services Ltd | Doncaster | 2010 |
| Climatemaster Limited | Grimsby | 1977 |
| Climateq Ltd | Bournemouth | 2010 |
| Climaterite Limited | Tamworth | 2017 |
| Climatic Services Limited | Glenrothes | 1986 |
| Climatic Ventilation Limited | Crewe | 2014 |
| Climatize Windows Ltd | Birmingham | 2022 |
| Climavent Systems Limited | St. Helens | 1997 |
| Climax Molybdenum U.K. Limited | Suffolk | 1940 |
| Climax Screen Hire Limited | Barnsley | 1997 |
| CLIMB8 Limited | Exeter | 2025 |
| Climbcare Ltd | Coventry | 2024 |
| Climbing Bouldering Supply Company Ltd | Kendal | 2020 |
| Climbing Frame Factory Limited | Armagh | 2017 |
| Climbing Turn Limited | Stevenage | 2009 |
| Climbing Wall Solutions Limited | Bristol | 2007 |
| Climec Driver Ltd | London | 2017 |
| Climpson & Sons Limited | London | 2009 |
| Clinch Coffee Ltd | Peterborough | 2025 |
| Clinch-It Ltd | Poole | 2021 |
| Cline (U.K.) Limited | London | 2015 |
| Clingbrook Limited | Downham Market | 1979 |
| Clingfoil Limited | Poynton Industrial Estate | 1982 |
| Clingz Grip Socks Ltd | Lutterworth | 2020 |
| Clingz Ltd | Lutterworth | 2020 |
| Clinical Build Limited | Harrow | 2024 |
| Clinical Design Technologies Group Ltd | Newton Abbot | 2026 |
| Clinical Design Technologies Limited | London | 2014 |
| Clinical Details Ltd | Basildon | 2023 |
| Clinical Engineering Services Ltd | Wigan | 2026 |
| Clinical Photopro Ltd | Chesham | 2019 |
| Clinical Polymer Technologies Ltd. | Coalville | 2005 |
| Clinical Print Finishers (U.K.) Limited | Leicestershire | 1993 |
| Cliniclogos.Ai CIC | Pinner | 2024 |
| Clinipol Holdings Ltd | Coalville | 2014 |
| Clinique Plus Ltd | Slough | 2020 |
| Cliniseal Ltd | London | 2020 |
| Clinivac Ltd | London | 2015 |
| Clinivex Group Ltd | London | 2020 |
| Clink Street FX Ltd | Cambridge | 2018 |
| Clinkah Ltd | London | 2024 |
| Clinks Cufflinks Limited | Croydon | 2008 |
| Clinkstone Brewing Company Ltd | Insch | 2019 |
| Clinogen Limited | Maidenhead | 2002 |
| Clinshore Limited | Barrow Upon Humber | 2006 |
| Clinstown Limited | Wolverhampton | 1978 |
| Clint's Custom Carpentry Limited | Gloucester | 2024 |