| Chris Brock Ltd | Administrative & support | 2020 |
| Chris Hughes Consulting Limited | Information & communication | 2020 |
| Chris Mahon Environment Ltd | Professional & scientific | 2018 |
| Christian Evidence Society(The) | Information & communication | 1934 |
| Christian Living Hub Ltd | Wholesale & retail | 2023 |
| Christie Kinge Associates Limited | Financial services | 2011 |
| Christie Prints Ltd | Manufacturing | 2023 |
| Christopher Bangs Ltd | Wholesale & retail | 2003 |
| Christopher Reeves Ltd | Professional & scientific | 2021 |
| Chroma Fushion Productions Ltd | Information & communication | 2025 |
| Chromium Group of Companies Ltd | Administrative & support | 2020 |
| Chromium Security Services Ltd | Financial services | 2019 |
| Chronopulseinfinity Ltd | Wholesale & retail | 2025 |
| Chrysantheum Ltd | Professional & scientific | 2020 |
| Chucky Chuckz Limited | Manufacturing | 2013 |
| Church Farm Pet Services Ltd | Agriculture & fishing | 2025 |
| Churchgate Acquisitions Limited | Financial services | 2023 |
| Churchgate Investment Properties Limited | Real estate | 2012 |
| Churchgate Trustees Limited | Administrative & support | 2012 |
| Churton Ltd | Information & communication | 2025 |
| Chuzzelwits Limited | Wholesale & retail | 2018 |
| CHV Beauty Ltd | Wholesale & retail | 2026 |
| Chylux Group Ltd | Wholesale & retail | 2025 |
| Ciage Ltd | Administrative & support | 2016 |
| Ciksorut Ltd | Hospitality | 2025 |
| Cilton Limited | Administrative & support | 2024 |
| Cinestructures International Limited | Professional & scientific | 1995 |
| CIO Magic Limited | Information & communication | 2025 |
| CIO Mirror CIC | Information & communication | 2025 |
| Circe London Ltd | Manufacturing | 2022 |
| Circuitcam Ltd | Extraterritorial | 2025 |
| Circular Cloud Ltd | Information & communication | 2014 |
| Circulation Solutions Limited | Construction | 2016 |
| Ciri Fruits Ltd | Wholesale & retail | 2014 |
| CIS Helpline Ltd | Administrative & support | 2026 |
| Citadel Projects Ltd | Construction | 2024 |
| Citibet Exchange Ltd | Arts & recreation | 2023 |
| Citibet Ltd | Arts & recreation | 2022 |
| Citium Advisory Ltd | Professional & scientific | 2025 |
| Citras Global Limited | Professional & scientific | 2025 |
| City Horse Racing Limited | Arts & recreation | 2016 |
| City Survivor Ltd | Wholesale & retail | 2017 |
| Cityconnect Solutions Ltd | Information & communication | 2020 |
| Civic Sparks Ltd | Professional & scientific | 2025 |
| Civils and Drainage Ltd | Administrative & support | 2024 |
| Civitas Marketing Ltd | Professional & scientific | 2016 |
| CJ & L Consultancy Ltd | Professional & scientific | 2021 |
| CJ Aviation Services Ltd | Manufacturing | 2023 |
| CJ Events Planning Ltd | Hospitality | 2025 |
| CJ Garner Ltd | Hospitality | 2019 |
| CJ Media Services Ltd | Professional & scientific | 2026 |
| CJ Surveys Ltd | Professional & scientific | 2012 |
| CJB Consulting Ltd | Professional & scientific | 2018 |
| CJH Consultants Ltd | Professional & scientific | 2026 |
| Cjjc Ltd | Health & social care | 2010 |
| Cjpf Limited | Hospitality | 2022 |
| CJT Equipment Ltd | Administrative & support | 2026 |
| CK Electrics Ltd | Construction | 2021 |
| CK Fleet Ltd | Hospitality | 2021 |
| Ckdj Limited | Real estate | 2026 |
| CKE Assets Limited | Construction | 2026 |
| CL Industries Ltd | Professional & scientific | 2023 |
| CL45 Limited | Hospitality | 2022 |
| Claas UK Limited | Wholesale & retail | 1949 |
| Claas Western Ltd | Wholesale & retail | 1955 |
| Clacei Ltd | Information & communication | 2026 |
| Claire Harrison Marketing Limited | Professional & scientific | 2024 |
| Claire Sambrook Coaching Ltd | Other services | 2019 |
| Clan Sussex Ltd | Health & social care | 2009 |
| Clancy Solutions Ltd | Information & communication | 2020 |
| Clapiz Houses Ltd | Real estate | 2024 |
| Clare Stringer Ltd | Education | 2021 |
| Clarence Radiance Ltd | Wholesale & retail | 2026 |
| Clarisen C.I.C. | Wholesale & retail | 2024 |
| Clarissa Grahn Ltd | Other services | 2022 |
| Claritas Legal & Compliance Ltd | Professional & scientific | 2026 |
| Claritas Prime Ltd | Hospitality | 2024 |
| Clarity EAR Care LLP | | 2021 |
| Clark and Mayston Limited | Health & social care | 2026 |
| Clark Bookkeeping Services Ltd | Professional & scientific | 2026 |
| Clarke & Clarke Investments Ltd | Real estate | 2025 |
| Clarkes of Walsham Limited | Wholesale & retail | 1954 |
| Clarke’S Virtual Solutions Ltd | Administrative & support | 2025 |
| Claronborne Limited | Real estate | 2024 |
| Class Couriers Ltd | Transport & logistics | 2026 |
| Classic Carbon Limited | Manufacturing | 2011 |
| Classic Hire Limited | Administrative & support | 2003 |
| Classical Toilet Hire Ltd | Extraterritorial | 2018 |
| Clavos&Mills Ltd | Hospitality | 2026 |
| Claxton Planning Services Limited | Professional & scientific | 2022 |
| Clay Target Shooting Academy Limited | Arts & recreation | 2018 |
| Clay Target Shooting Activities Limited | Arts & recreation | 2018 |
| Clay Target Shooting Associates Limited | Arts & recreation | 2018 |
| Clayton Property Services Ltd | Real estate | 2026 |
| Clean Accounts Ltd | Professional & scientific | 2022 |
| Clean Shine Creations Ltd | Administrative & support | 2026 |
| Clean Slate Roof Cleaning Ltd | Administrative & support | 2024 |
| Clean Your Clutter Ltd | Administrative & support | 2024 |
| Cleaning and Grounds Property Services Limited | Administrative & support | 2024 |
| Cleaning Standardisation Group Limited | Professional & scientific | 2021 |