| CL Training Ltd | Professional & scientific | 2022 |
| Clacton Associates Ltd | Information & communication | 2024 |
| Claire Career Consulting Limited | Professional & scientific | 2021 |
| Claire Freeman Consulting Limited | Professional & scientific | 2017 |
| Claire Lynch Consulting Ltd | Professional & scientific | 2021 |
| Clap Pubs Limited | Hospitality | 2019 |
| Clapu Construct Ltd | Construction | 2018 |
| Clara Care Ltd | Health & social care | 2025 |
| Clare Brooke-Little Limited | Professional & scientific | 2014 |
| Clarity Coaching and Leadership Limited | Professional & scientific | 2025 |
| Clarity Copiers (High Wycombe) Limited | Administrative & support | 2001 |
| Clark's of Amersham Limited | Transport & logistics | 2004 |
| Clarke & Allen Gardeners Limited | Administrative & support | 2000 |
| Clarke Independent Limited | Financial services | 2008 |
| Clarke Independent Properties Limited | Real estate | 2017 |
| Clarkey Sparkie Limited | Construction | 2008 |
| Clark’S Film Animals Ltd | Arts & recreation | 2025 |
| Classic Freight Holdings Limited | Transport & logistics | 2022 |
| Classy Stone Ltd | Professional & scientific | 2022 |
| Clawar Association Limited | Professional & scientific | 2006 |
| Claydon Community Café CIC | Health & social care | 2019 |
| Claydon Fire Solutions Ltd | Construction | 2026 |
| Clayfield Estates Limited | Construction | 2020 |
| Claymoor Group Ltd | Real estate | 2019 |
| Claymoor Holdings Ltd | Real estate | 2019 |
| Claymoor Investments Limited | Real estate | 2024 |
| Claymoor Ltd | Real estate | 2024 |
| Claymoor Management Ltd | Real estate | 2019 |
| Clayton Davis Enterprises Ltd | Wholesale & retail | 2025 |
| Cldconsultancy Ltd | Health & social care | 2022 |
| Clean and Shiny Group Ltd | Administrative & support | 2026 |
| Clean Control UK Ltd | Administrative & support | 2018 |
| Cleancoat Property Services Ltd | Construction | 2026 |
| Cleanevent Properties Limited | Real estate | 2023 |
| Cleanevent Services Limited | Administrative & support | 2016 |
| Cleaning Services of Ascot Ltd | Administrative & support | 2024 |
| Clear Choice 22 Ltd | Construction | 2022 |
| Clear Environment (Office Clearance) Ltd | Wholesale & retail | 2008 |
| Clear Environment Limited | Wholesale & retail | 2022 |
| Clear Sealed Units Ltd | Manufacturing | 2021 |
| Clear Way Forward Ltd | Administrative & support | 2013 |
| Clearcare Healthcare Ltd | Public administration | 2020 |
| Clearcove Limited | Information & communication | 2006 |
| Clearfast Freight Services Ltd | Transport & logistics | 2020 |
| Clearfast Services Limited | Administrative & support | 2006 |
| Clearly Obvious Limited | Professional & scientific | 2005 |
| Clearsky Solutions Limited | Information & communication | 2021 |
| Cleartel Solutions Ltd | Manufacturing | 2020 |
| Cleartext Ltd | Hospitality | 2011 |
| Clearway Computing Limited | Information & communication | 2013 |
| Clearway Waste Removal Ltd | Water & waste | 2024 |
| Cleeve Fire Protection Limited | Administrative & support | 2002 |
| Clement V T Limited | Wholesale & retail | 2019 |
| Cleo Cafe Ltd | Hospitality | 2026 |
| Clermont Energy Partners LLP | | 2008 |
| Clever Companies Group Limited | Information & communication | 2022 |
| Click & Go Ltd | Wholesale & retail | 2025 |
| Click Cart HW Ltd | Wholesale & retail | 2024 |
| Clicknshop Limited | Wholesale & retail | 2012 |
| Clicqa Software Testing Ltd | Information & communication | 2021 |
| Clicsource Ltd | Information & communication | 2019 |
| Cliddesdon Reach Management Company Limited | Extraterritorial | 2005 |
| Cliff Cars Limited | Transport & logistics | 2013 |
| Cliff's Coaches Ltd | Transport & logistics | 2011 |
| Cliff's Minibuses Limited | Transport & logistics | 2014 |
| Clifton Taverns Ltd | Hospitality | 2026 |
| Climate Building Services Ltd | Manufacturing | 2002 |
| Climate Construction Ltd | Construction | 2026 |
| Climespan AI Limited | Information & communication | 2026 |
| Clinical Productions Ltd | Arts & recreation | 1998 |
| Clinically Significant Ltd. | Health & social care | 2012 |
| Clinispace Ltd | Real estate | 2020 |
| Clipper Investments Limited. | Extraterritorial | 1985 |
| Clive Knowles Carpentry Limited | Construction | 2013 |
| Cliveden Medical Limited | Health & social care | 2011 |
| Cliveden Property Limited | Construction | 2016 |
| Cloke & Dagger Limited | Construction | 2017 |
| Clostu Studios Ltd | Wholesale & retail | 2022 |
| Cloth&Pocket Ltd | Wholesale & retail | 2025 |
| Cloud 13 Ltd | Information & communication | 2013 |
| Cloud AI Data Tech Ltd | Information & communication | 2026 |
| Cloud Village Ltd | Information & communication | 2024 |
| CLOWD9 Ltd | Other services | 2019 |
| Club Car Wash & Valeting Limited | Administrative & support | 2023 |
| Club Shop Goodies Limited | Administrative & support | 2012 |
| Clutch Talent Group Ltd | Administrative & support | 2026 |
| CM Communications Limited | Wholesale & retail | 2011 |
| CM Communications Online Ltd | Other services | 2020 |
| CM Pension Administrators Ltd | Financial services | 2014 |
| CM Properties Services Ltd | Real estate | 2020 |
| CMB Building Services Ltd | Construction | 2014 |
| CML Sales and Lettings Ltd | Real estate | 2024 |
| CML Trade Ltd | Wholesale & retail | 2017 |
| Cmpm Limited | Professional & scientific | 2008 |
| CMS Building (London) Ltd | Construction | 2011 |
| CMS Holdings Partnership Limited | Financial services | 2025 |
| CNF Holdings Limited | Other services | 2018 |
| Cnicht Limited | Wholesale & retail | 2024 |
| CNP Supplements Limited | Wholesale & retail | 2021 |
| CNY Limited | Real estate | 2024 |