| Clear Sky Mortgage Solutions Ltd | Financial services | 2015 |
| Clear Spill Limited | Manufacturing | 1978 |
| Clear Thoughts Ltd | Health & social care | 2023 |
| Clear View Clean Solutions Limited | Administrative & support | 2024 |
| Clear Vision (UK) Limited | Real estate | 2014 |
| Clear Vision Learning Ltd | Professional & scientific | 2014 |
| Clear-K Limited | Wholesale & retail | 2018 |
| CLEARCOVERWARRANTIES.COM2 Limited | Wholesale & retail | 2023 |
| Clearderma Limited | Health & social care | 2017 |
| Cleared Carpenters Ltd | Construction | 2023 |
| Clearer Communications Limited | Professional & scientific | 2004 |
| Clearer Ltd | Professional & scientific | 2024 |
| Clearer.Io UK Ltd | Information & communication | 2022 |
| Clearfin Limited | Professional & scientific | 2020 |
| Clearglaze Windows & Doors Ltd | Manufacturing | 2022 |
| Clearguard Limited | Administrative & support | 2006 |
| Clearhear Solutions Ltd | Wholesale & retail | 2023 |
| Clearoute Ltd | Administrative & support | 2012 |
| Clearspace Groundcare Solutions Ltd | Construction | 2019 |
| Clearstead Ltd | Real estate | 2026 |
| Clearview Environmental Ltd | Construction | 2015 |
| Clearvision Optics Ltd | Health & social care | 2021 |
| Clearvue Window Cleaners Ltd | Administrative & support | 2024 |
| Clearwater Aquatics Limited | Wholesale & retail | 2010 |
| Clearwater Property Compliance Ltd | Administrative & support | 2026 |
| Clearwell Proficiency Ltd | Transport & logistics | 2015 |
| Cleaveleand Prop Limited | Real estate | 2015 |
| Clemmie Bar Ltd | Hospitality | 2025 |
| Clenviro Holdings Ltd | Financial services | 2022 |
| Clenviro Ltd | Manufacturing | 2004 |
| Clenzora Ltd | Manufacturing | 2026 |
| Cleopian Ltd | Information & communication | 2017 |
| Cleteco Energy Ltd | Professional & scientific | 2025 |
| Clevedon Spice Limited | Hospitality | 2015 |
| Cleverhome Automation Ltd | Information & communication | 2010 |
| Cleves Taverns (Black Horse) Limited | Hospitality | 2019 |
| Clews & Co Construction Limited | Construction | 2025 |
| Clgl Estates Limited | Real estate | 2020 |
| Click & Go Stores Retail Ltd | Wholesale & retail | 2026 |
| Click Ace Ltd | Professional & scientific | 2021 |
| Click and Stay Limited | Hospitality | 2019 |
| Click Software Limited | Information & communication | 2010 |
| CLICK2BUILD Limited | Construction | 2019 |
| CLICK3CLICK Ltd | Wholesale & retail | 2016 |
| CLICK4PICK Ltd | Wholesale & retail | 2025 |
| Clickcasa Ltd | Information & communication | 2026 |
| CLICKE83 Ltd | Transport & logistics | 2013 |
| Clicknget Limited | Wholesale & retail | 2017 |
| Clickroo Ltd | Wholesale & retail | 2025 |
| Clickwel Limited | Wholesale & retail | 2025 |
| Clientpath Ltd | Professional & scientific | 2026 |
| Cliffe Houses Ltd | Real estate | 2026 |
| Clifford Catering Limited | Wholesale & retail | 2007 |
| Clifford Plumbing & Bathrooms Ltd | Construction | 2025 |
| Cliffords Estates Limited | Real estate | 2003 |
| Cliffsend Ideal Ltd | Administrative & support | 2015 |
| Clifton Consults Ltd | Professional & scientific | 2024 |
| Clifton Dining Ltd | Hospitality | 2022 |
| Clifton Packaging Group Limited | Manufacturing | 2002 |
| Climaflow Limited | Wholesale & retail | 2024 |
| Climatehomes Ltd | Construction | 2025 |
| Climb Group Property Limited | Real estate | 2019 |
| Clindoc Limited | Health & social care | 2016 |
| Clinevo London Ltd | Health & social care | 2023 |
| Clinibot Ltd | Information & communication | 2024 |
| Clinic D Ltd | Health & social care | 2021 |
| Clinical Audit Support Centre Limited | Professional & scientific | 2006 |
| Clinical Digital Partners Ltd | Information & communication | 2025 |
| Clinical Edge Limited | Administrative & support | 2010 |
| Clinical Psych Ltd | Health & social care | 2022 |
| Clinical-Ink Limited | Other services | 2023 |
| Clinicpharm Limited | Other services | 2022 |
| Clinique DE Beaute Limited | Other services | 2010 |
| Clint Cutz Limited | Other services | 2019 |
| Clintrials Limited | Professional & scientific | 2016 |
| Clio Peppiatt Holdings Ltd | Financial services | 2024 |
| Clio Peppiatt Ltd | Arts & recreation | 2018 |
| Clipper Contracts Limited | Construction | 1988 |
| Clipper Properties Leicester Limited | Real estate | 2016 |
| Clippits Motorsport Limited | Arts & recreation | 2021 |
| Clique Universal Limited | Wholesale & retail | 2025 |
| Clive D. Smith Trading . Ltd | Transport & logistics | 2020 |
| Clive Ruggles Limited | Information & communication | 2006 |
| Cljm Limited | Arts & recreation | 2018 |
| CLL Property Holdings Limited | Financial services | 2023 |
| Clna Data Exchange Limited | Professional & scientific | 2025 |
| Clock Brown Limited | Real estate | 2019 |
| Clock Chambers Therapy Rooms Ltd | Health & social care | 2026 |
| Clockpad Limited | Real estate | 2018 |
| Cloisters Financial Management Limited | Financial services | 2003 |
| Cloke Ltd | Financial services | 2026 |
| Closer Care Services Limited | Administrative & support | 2023 |
| Clothing 4 YOU Ltd | Wholesale & retail | 2026 |
| Clothing Design Studio Limited | Manufacturing | 2010 |
| Cloud 55 Ltd | Information & communication | 2019 |
| Cloud 9 Desserts Ltd | Hospitality | 2018 |
| Cloud AI Technologies Ltd | Extraterritorial | 2023 |
| Cloud Benefits Limited | Information & communication | 2019 |
| Cloud DE Silva Ltd | Hospitality | 2023 |
| Cloud Distributors Limited | Wholesale & retail | 2023 |