| Church Missionary Trust Association Limited | Oxford | 1913 |
| Church Park Construction Limited | Leeds | 2020 |
| Church Park Developments Limited | Leeds | 2019 |
| Church Park Homes Limited | Leeds | 2019 |
| Church Road Property (Linslade) Ltd | Leighton Buzzard | 2023 |
| Church Road Property Management Ltd | Ballyclare | 2007 |
| Church Street Brighton RTM Company Limited | Brighton | 2026 |
| Church Street Models Limited | Hampshire | 2007 |
| Churchdale Homes Ltd | Wakefield | 2000 |
| Churchdown Consulting Ltd | Fawkham | 2022 |
| Churches' Enterprise Limited-The | Londonderry | 1992 |
| Churchgate Day Nursery Limited | Manchester | 2019 |
| Churchill (Scotland) Properties Limited | Renfrewshire | 1999 |
| Churchill Collections Limited | London | 2022 |
| Churchill Estates Limited | London | 2014 |
| Churchill Lightning Protection Limited | Nottingham | 2003 |
| Churchill Park Food Market Limited | Craigavon | 2001 |
| Churchill Road (Freehold) Ltd | Colchester | 2012 |
| Churchill Steeplejacks (U.K.) Limited | Nottingham | 2010 |
| Churchill Way Finance (Newport) Limited | Cardiff | 1970 |
| Churchills Homes (Southern) Limited | London | 2008 |
| Churchills Winning Concepts Limited | Walsall | 2012 |
| Churchley Bros.Limited | Solihull | 1961 |
| Churchley Builders Plastics Limited | Solihull | 1994 |
| Churchmill Limited | Godalming | 2019 |
| Churchmoore Limited | London | 2012 |
| Churchmouse Limited | Manningtree | 2022 |
| Churchside Manor Management Company Ltd | Belfast | 2006 |
| Churchstoke Laundry Limited | Shrewsbury | 2020 |
| Chute Fire Certification UK Limited | Cheadle | 2017 |
| CHY Designs Limited | Northampton | 2023 |
| Chydon Limited | Bury | 2021 |
| CI Bearings Ltd | Bushey | 1994 |
| CI Coaching Ltd | Bradford | 2019 |
| Cian Creative PR Limited | Durham | 2011 |
| Ciao Bella Agency Ltd | Crawley | 2012 |
| Ciaoco Ltd | Manchester | 2023 |
| Ciaran ROY Turner Limited | London | 2025 |
| Ciartech Limited | Epsom | 2015 |
| Ciba Apartments Limited | London | 2000 |
| Ciberdank Limited | London | 2023 |
| Cibus Limited | Southampton | 2013 |
| CIC Photographic Limited | Preston | 2018 |
| Cicilia Limited | Milton Keynes | 2023 |
| Cidel Financial Group Ltd | London | 2002 |
| Cider Tree Partners Limited | Marlborough | 2018 |
| Cidon Holdings Limited | Barnsley | 2016 |
| Ciegt Ltd | Prestbury | 2015 |
| Ciem UK Ltd | Worcester | 2019 |
| Cifl Channel Islands Fuels Limited | Birchwood | 2011 |
| Cig-Ease Ltd. | Chorley | 2013 |
| Ciga Limited | Leighton Buzzard | 2006 |
| Cigars Limited | London | 2022 |
| Cigarvogue Ltd | Harrogate | 2025 |
| CII International Limited | Richmond | 2018 |
| Ciiir Limited | Wembley | 2023 |
| CIJ Realty Ltd | Kent | 2025 |
| CIL Realisations Limited | London | 2024 |
| Cilaisen (UK) Electronic Technology Co., Ltd | Coventry | 2018 |
| Cilita Ltd | Kington | 2012 |
| Cilmeri Limited | Boncath | 2005 |
| CIM Direct Limited | Maidenhead | 1991 |
| CIM Holdings Limited | Maidenhead | 1991 |
| CIM Trade Ltd | London | 2023 |
| Cima Technology Ltd | London | 2011 |
| Cimc Vehicles Sales Co., Ltd. | London | 2015 |
| Cimla Properties Limited | Llanelli | 2014 |
| Cimrie Limited | London | 2025 |
| Cimva Limited | Padstow | 2025 |
| CIN Properties Limited | London | 2009 |
| Cinch Ltd | Hook | 2022 |
| Cinder Pulse Ltd | London | 2025 |
| Cinderpath Ltd | Doncaster | 2026 |
| Cinderpath Solutions Ltd | Doncaster | 2026 |
| Cinderpeak AI Ltd | Doncaster | 2026 |
| Cinders Barns Management Company Limited | Bewdley | 2021 |
| Cine Creative Ltd | West Byfleet | 2024 |
| Cine Power & Light International Limited | Exeter | 2001 |
| Cine Power Consultancy & Design Ltd | Exeter | 2001 |
| Cine Wings Ltd | Stockport | 2020 |
| Cinecity Limited | London | 1976 |
| Cinema Luxe Contracts Ltd | Colchester | 2023 |
| CINEMA101 Ltd | Grimsby | 2018 |
| Cinematique Film Company Ltd | Falkirk | 2012 |
| Cinemoto Ltd | London | 2026 |
| Cineplan Ltd | Brighton | 2025 |
| Cineworld Cinema Properties Limited | Brentford | 1932 |
| Cineworld Elite Picture Theatre (Nottingham) Limited | Brentford | 1919 |
| Cineworld South East Cinemas Limited | Brentford | 1928 |
| Cinhan Ltd | Bournemouth | 2019 |
| Cinisco Ltd | Swanage | 2015 |
| Cinjos Limited | Salford | 2003 |
| Cinjos Oxford Limited | Salford | 2020 |
| Cinnamon Daisy Ltd | Huddersfield | 2023 |
| Cinnlois 08 Limited | Cheltenham | 2020 |
| Cintride Limited | Sheffield | 2001 |
| CIO Global Ltd | London | 2024 |
| CIP Network Ltd | Larne | 2015 |
| Cipall Limited | Cardiff | 2022 |
| Cipherbloom Investment Partners Ltd | Manchester | 2025 |