| Conservation Matters Ltd | Blandford Forum | 2014 |
| Conserve Paintings Ltd | Leigh-On-Sea | 2025 |
| Consett & District Golf Club,Limited(The) | Consett | 1968 |
| Consett AFC Ltd | Stanley | 2013 |
| Consett and District Heritage and Arts Community Interest Company | Consett | 2019 |
| Consett Association Football Club Ltd | Consett | 2026 |
| Consider the Wondrous CIC | Hereford | 2026 |
| Considered Composition Limited | London | 2019 |
| Consistency BJJ Ltd | London | 2023 |
| Consistent Fitness Ltd | Birmingham | 2025 |
| Consol Suncenter (South East) Limited | Axbridge | 2008 |
| Console Gaming Ltd | Willenhall | 2022 |
| Consolidated Archive Holdings Limited | Sutton | 2017 |
| Consolidated Artistes Limited | Barnet | 2024 |
| Consolidated Fuzz Limited | Sheffield | 2014 |
| Consop Live Ltd | London | 2025 |
| Consort Communications Limited | London | 1998 |
| Consort Fitness Limited | Shelf | 2002 |
| Consort Productions Ltd | Barnstaple | 2016 |
| Consortium International Ltd | London | 2015 |
| Consortium of European Research Libraries | London | 1994 |
| Conspiracy Books Ltd | London | 1997 |
| Conspirator's Kitchen Limited | London | 2002 |
| Constama Ltd | Haywards Heath | 2026 |
| Constant Fitness Ltd | Portsmouth | 2021 |
| Constant Pursuit Crossfit Ltd | Bexhill-On-Sea | 2022 |
| Constantia Brothers Music Limited | Norwich | 1987 |
| Constantia Pictures Limited | Bromsgrove | 2015 |
| Constellate Talent Ltd | London | 2020 |
| Constellation Points Ltd. | Thornhill | 2015 |
| Constellations Management Ltd | London | 2013 |
| Constest Events Limited | Birmingham | 2024 |
| Construction Accessories Limited | Walsall | 1984 |
| Constructive Creative Ltd | Reading | 2017 |
| Constructive Music Ltd | Chelmsford | 2020 |
| Constructive Racing Ltd | Writtle | 2026 |
| Consulting W8 Ltd | London | 2023 |
| Consulto Aptior Limited | London | 2024 |
| Consultridge Limited | London | 2024 |
| Consylowe Limited | Teddington | 2015 |
| Contact Events Limited | Manchester | 2020 |
| Contact Point Coach Ltd | London | 2026 |
| Contained Creatives Limited | Oxford | 2019 |
| Contained Wellness Ltd | Hemel Hempstead | 2024 |
| Containment Ltd. | Kingston Upon Thames | 2014 |
| Contego Media Group Ltd | Bristol | 2017 |
| Contempo Art Japon Limited | London | 2010 |
| Contempo Productions Ltd | Wigan | 2012 |
| Contemporary Applied Arts | London | 1967 |
| Contemporary Art Keen Enthusiast Ltd | London | 2010 |
| Contemporary Art Society(The) | London | 1931 |
| Contemporary Choir Ltd | Bewdley | 2018 |
| Contemporary Clowning Projects | London | 2004 |
| Contemporary Culture Collective Ltd | London | 2024 |
| Contemporary Glass Society | Brackley | 2004 |
| Contemporary LAB Ltd | London | 2021 |
| Contemporary Media Music Productions Limited | Whyteleafe | 1985 |
| Contemporary Music for ALL | London | 1997 |
| Contemporary Original Art Limited | London | 2024 |
| Contemporary Tributes Ltd | London | 2026 |
| Contemporary TV Limited | London | 1988 |
| Contenders Limited | Great Yarmouth | 2016 |
| Contenders West Bromwich Boxing Club | Tipton | 2025 |
| Content Consultants Limited | Norwich | 2001 |
| Content Corporation Ltd | Sheffield | 2011 |
| Content Creative 2025 Ltd | London | 2025 |
| Content Creative Media Ltd | Borehamwood | 2017 |
| Content Kings Connect Ltd | London | 2025 |
| Contento Pilates Ltd | Cambridge | 2025 |
| Contessa 26 Class Association Limited | Lake | 2018 |
| Context Management Limited | London | 2024 |
| Contexture Theatre Limited | Bishop'S Stortford | 2013 |
| Conti Productions Ltd | Mildenhall | 2023 |
| Continental Drifts Ltd | Walthamstow | 1996 |
| Continental Leisure Projects Limited | Cheshire | 2016 |
| Continental Leisure Projects Markets Limited | Ellesmere Port | 2016 |
| Continental Pictures Limited | Middlesex | 1987 |
| Continental Tech Partners Ltd | London | 2021 |
| Continue Arcades Ltd | Plymouth | 2023 |
| Continuous Artistic Development Studio Limited | London | 2012 |
| Continuous Motion Ltd | Bristol | 2025 |
| Continuum (Entertainment) Limited | York | 1985 |
| Continuum (Loch Ness) Limited | York | 2018 |
| Continuum Sport and Leisure Ltd | London | 2001 |
| Contortion Space CIC | London | 2025 |
| Contour Events Ltd | Kilmarnock | 2020 |
| Contour Forge Ltd | London | 2025 |
| Contoured Reformer Pilates Ltd | Stockport | 2025 |
| Contra Productions Ltd | Bristol | 2023 |
| Contraband Events Ltd | London | 2018 |
| Contrast Entertainment Ltd | Leyland | 2023 |
| Contrast Recovery & Wellness Ltd | Winchester | 2026 |
| Contrast Wellness Club Limited | Porth | 2024 |
| Contrepoint Limited | London | 2024 |
| Control Core Ltd | London | 2025 |
| Control Frame Ltd | London | 2025 |
| Controlaball Ltd | London | 2013 |
| Controldec Media Limited | Hamilton | 2023 |
| Controlled Chaos Entertainment Ltd | Bexhill-On-Sea | 2026 |
| Controlled Fade Golf Ltd | Eastwick | 2015 |