| Civil Engineering Developments Limited | Rochford | 1988 |
| Civil Engineering Dynamics Ltd | Purley | 2025 |
| Civil Labour Limited | Horbury | 2024 |
| Civil Service Networks | London | 2025 |
| Civil Solutions Scotland Ltd | Perth | 2020 |
| Civilbray Limited | London | 1985 |
| Civils Connect Ltd | Birmingham | 2025 |
| Cixi Alpha Bearing Company Limited | Beckenham | 2018 |
| Cixi City Sharmoon Electric Co., Ltd | Beckenham | 2022 |
| Cixi Meka Machine Parts Co., Ltd | Beckenham | 2019 |
| Cixi Ruijing Components Co., Ltd | Manchester | 2011 |
| Cixi Xinfeng Machinery Co., Ltd. | Cardiff | 2016 |
| CIY LED Limited | London | 2013 |
| Cizrebotan Yachting Company Ltd | London | 2025 |
| CJ Asset Holdings Ltd | St Ives | 2025 |
| CJ Coaches Limited | Stanley | 2013 |
| CJ Cube Limited | Glasgow | 2023 |
| CJ E-Technology Ltd | London | 2020 |
| CJ Holland Contracting Limited | Dudley | 2006 |
| CJ Horizons Ltd | Rugeley | 2014 |
| CJ Properties Estate Agents Limited | Kingston Upon Hull | 2009 |
| Cj's @ Europa Ltd | Grays | 2011 |
| CJA Digital Limited | London | 1973 |
| CJB Associates Ltd | Watton | 2014 |
| CJB Carpentry Contractors Ltd | Bude | 2014 |
| CJB Management Services Limited | Coventry | 2020 |
| CJB Today Ltd | London | 2026 |
| CJC Computer Solutions Ltd | Birmingham | 2022 |
| CJC Newco 6 Limited | Manchester | 2013 |
| CJC Painting Contractors Limited | Greenhithe | 2013 |
| Cjch Legal (Holdings) Limited | Cardiff | 2024 |
| CJD Developments Limited | Stanford-Le-Hope | 2012 |
| CJH Davies & Sons Ltd | Market Harborough | 2016 |
| CJH Plant and Tool Hire Limited | Skegness | 2015 |
| CJJ Construction Limited | Dover | 2019 |
| CJL Trustees Ltd | Edinburgh | 2022 |
| CJM Investment Management Ltd | Edinburgh | 2012 |
| CJP (2014) Holdings Ltd | Whitefield | 2014 |
| CJS Care (Northampton) Ltd | Northampton | 2019 |
| CJS Electrical Solutions PV & EV Installations Ltd | Manchester | 2022 |
| CJW Electrical and Data Solutions Ltd | St. Neots | 2006 |
| CJW Logistics Ltd | Wakefield | 2023 |
| Cj’S Electrical Solutions NW Ltd | Manchester | 2022 |
| CK & G UK Limited | Oldham | 2016 |
| CK Autotie Balers Ltd | Dungannon | 2012 |
| CK Beauty Therapy Limited | Aberdeen | 2020 |
| CK Consultants Ltd | Letchworth Garden City | 2020 |
| CK Direct Group Limited | Peterborough | 2016 |
| CK Friskvard I Vast Investment Limited | London | 2022 |
| CK Friskvard I Vast Limited | London | 2022 |
| CK Marine Service Ltd | Cambridge | 2016 |
| CK Special Gases Limited | Crewe | 2020 |
| CK Supplies Limited | Manchester | 2014 |
| CK Technology Holdings Alpha Limited | London | 2024 |
| Ckbt Lettings Ltd | Halesowen | 2019 |
| Ckcentral Ltd | Stone | 2022 |
| Ckcs Plymouth Ltd | Plymouth | 2021 |
| Ckdn Nutrition Ltd | Prenton | 2022 |
| Ckkc Limited | Spalding | 2019 |
| CKN Trading INT. Limited | London | 2020 |
| Ckor Limited | Ashford | 2013 |
| CKP Property Developments Limited | Blackwood | 2012 |
| Ckpress Group Limited | London | 1993 |
| CKR Nominees Limited | Dartford | 2000 |
| CKR4 Limited | Dartford | 2024 |
| CKS Projects Limited | Christchurch | 2015 |
| CL Accommodations Ltd | Cleckheaton | 2023 |
| CL Land and Properties Limited | Nantwich | 2022 |
| CL Management Ltd | London | 2015 |
| CL1VE Limited | Harrogate | 2020 |
| Claarity Ltd | London | 2024 |
| Clacton Wellbeing Centre Limited | Colchester | 2018 |
| Cladding Consultants (UK) Limited | Weymouth | 2004 |
| Cladding Direct Online Ltd | Glasgow | 2021 |
| Cladding Sheets & Profiles Limited | Smethwick | 1976 |
| Claessens Design Limited | London | 1989 |
| Claessens International London Limited | London | 2009 |
| Claessens Limited | London | 1994 |
| Claessens Production and Artwork Services Limited | London | 1989 |
| Claim Again Ltd | Hull | 2009 |
| Claim Easy Limited | Knutsford | 2024 |
| Claim Validation Technologies Limited | Cheltenham | 2011 |
| Claimant Advice Bureau Limited | Willenhall | 2020 |
| Claimline Limited | Manchester | 2008 |
| Claims Consortium (Group) Limited | Taunton | 2013 |
| Claims Consortium Limited | Taunton | 2013 |
| Claims Consultants (UK) Limited | Sidcup | 2022 |
| Claimsline UK Limited | Royston | 2013 |
| Claimsupermarket.Com Limited | Deeside | 2003 |
| Claire Cook Counselling and Psychotherapy Ltd | Bristol | 2025 |
| Claire DE LA Lune Ltd | Enfield | 2021 |
| Claire Enders Limited | Dundee | 2000 |
| Claire Goldsmith Eyewear Ltd | London | 2008 |
| Claire Lloyd Properties Limited | Camberley | 2006 |
| Claire Michelle Buckett Limited | Oxford | 2022 |
| Claire Presents Limited | Twickenham | 2024 |
| Claire Wealleans Limited | Cramlington | 2022 |
| Claj Properties Limited | Chester | 2016 |
| Clajm Life Ltd | Haverfordwest | 2022 |
| Clamp Bros Events Hire Limited | Solihull | 2018 |