| Clickswoven Ltd | Wholesale & retail | 2024 |
| Client Secure UK Ltd | Administrative & support | 2018 |
| Clientology Ltd | Other services | 2017 |
| Clifden Court Management Limited | Real estate | 1994 |
| Cliff Property Investments Ltd | Real estate | 2026 |
| Cliff Studio Ltd | Professional & scientific | 2016 |
| Clifford LEE Limited | Arts & recreation | 2025 |
| Clifford Social Care Limited | Health & social care | 2026 |
| Clifton Arms PUB Ltd | Hospitality | 2025 |
| Clifton Capital Inc Ltd | Professional & scientific | 2024 |
| Clikhealth Solutions Ltd | Information & communication | 2011 |
| Clim Logistics Ltd | Transport & logistics | 2026 |
| Climant Ltd | Construction | 2024 |
| Climaseal UK Limited | Extraterritorial | 2012 |
| Climate Core Ltd | Construction | 2025 |
| Climax Scaffolding Ltd. | Construction | 2001 |
| Climb Property Ltd | Real estate | 2019 |
| Clinic 47 Ltd | Other services | 2022 |
| Clinica-Care Health Solutions Ltd | Health & social care | 2025 |
| Clinical Aesthetics Group Ltd | Health & social care | 2016 |
| Clinical Law Ltd | Extraterritorial | 2012 |
| Clinical Neuropsychology Services Ltd. | Health & social care | 2012 |
| Clinique Solutions Ltd | Health & social care | 2025 |
| Clinton Project Management Limited | Construction | 2013 |
| Clipnotes Limited | Real estate | 1988 |
| Clippers Quay (South Ferry Island) Management Company Limited | Households | 1999 |
| Cliq Car Care Ltd | Administrative & support | 2026 |
| Clique Ltd | Wholesale & retail | 2018 |
| Clique Property Development Ltd | Real estate | 2024 |
| Cliquesy Ltd | Professional & scientific | 2023 |
| CLJ Developments Ltd | Construction | 2019 |
| CLJ Group Limited Ltd | Construction | 2025 |
| CLJ PUB Co Limited | Hospitality | 2026 |
| CLJ Wind Ltd | Manufacturing | 2026 |
| CLK Commercials Ltd | Wholesale & retail | 2024 |
| CLK Recovery Ltd | Transport & logistics | 2024 |
| Cllb Services Ltd | Professional & scientific | 2022 |
| CLO Properties Limited | Real estate | 2024 |
| Clock Tower Park Management Limited | Other services | 2023 |
| Clockface Kennels (ST. Helens) Limited | Administrative & support | 2006 |
| Clockwork Accounting Limited | Professional & scientific | 2018 |
| Clockwork Club Ltd | Extraterritorial | 2016 |
| Clockwork FOX Production's Dark Reality CIC | Information & communication | 2024 |
| Clockworks Steakhouse Ltd | Hospitality | 2023 |
| Clodar Limited | Real estate | 2022 |
| Clomac Ltd. | Manufacturing | 1999 |
| Clomas Safety and Access Limited | Construction | 2025 |
| Clone Centre Ltd | Information & communication | 2025 |
| Close Family Trading Company Trading Limited | Professional & scientific | 2021 |
| Cloth Converters Ltd | Manufacturing | 2025 |
| Clothing by Nola Ltd | Wholesale & retail | 2025 |
| Clothing Connection Ltd | Wholesale & retail | 2020 |
| Clotworthy Property Ltd | Real estate | 2025 |
| Cloud & Candy Store Limited | Wholesale & retail | 2025 |
| Cloud 8 Formby Ltd | Other services | 2024 |
| Cloud 9 Childrenswear Limited | Wholesale & retail | 2018 |
| Cloud Beauty Limited | Wholesale & retail | 2023 |
| Cloud Environment and Quality Management Systems Ltd | Professional & scientific | 2020 |
| Cloud Way Limited | Wholesale & retail | 2025 |
| CLOUD9ADULTS Ltd | Wholesale & retail | 2023 |
| CLOUD9SHOP Limited | Wholesale & retail | 2023 |
| Cloudside Associates Limited | Professional & scientific | 2011 |
| Cloudsource Recruitment Ltd | Administrative & support | 2013 |
| Cloudsys Analytics Limited | Information & communication | 2021 |
| Cloudtop Agrofoods International Limited | Wholesale & retail | 2019 |
| Cloudvertex Solutions Ltd | Information & communication | 2026 |
| Cloust Delivery Ltd | Transport & logistics | 2025 |
| Clover Auto Parts Limited | Wholesale & retail | 2018 |
| Clover Business Consultancy Ltd | Information & communication | 2021 |
| Clover Collections Ltd. | Administrative & support | 2011 |
| Clover Commercial Property Limited | Real estate | 2019 |
| Clover Estates Ltd | Real estate | 2017 |
| Clover Holdings Limited | Financial services | 2017 |
| Clover Industrial Investments Limited | Wholesale & retail | 2018 |
| Clover Truck and Plant Hire Limited | Water & waste | 2020 |
| Cloverjack Stores Limited | Wholesale & retail | 2019 |
| CLP Cleaning Services Ltd | Administrative & support | 2025 |
| CLP Designs Ltd | Other services | 2010 |
| CLS Motors Ltd | Wholesale & retail | 2025 |
| CLS Surgical Ltd | Wholesale & retail | 2007 |
| CLT@ Adhdtitrations Ltd | Health & social care | 2022 |
| Cluain ARD Consulting Services Limited | Construction | 2013 |
| Club Apparel Ltd | Wholesale & retail | 2022 |
| Club Ariaa Limited | Professional & scientific | 2025 |
| Club DE Reve Ltd | Wholesale & retail | 2025 |
| Club Development Circle Limited | Education | 2026 |
| Club Properties NW Ltd | Real estate | 2026 |
| Club Sport Ltd | Other services | 2003 |
| CLUB3000 Leisure Ltd | Arts & recreation | 2008 |
| Clubco Limited | Administrative & support | 2007 |
| Clubhouse Cafe Formby Ltd | Hospitality | 2022 |
| Clubmoor Barber Ltd | Other services | 2025 |
| Clubmoor Builders Ltd | Construction | 2010 |
| Clubmoor Home Improvements Limited | Wholesale & retail | 2017 |
| Clubmoor Nursery Ltd | Health & social care | 2021 |
| Cluck and Crunch Limited | Hospitality | 2025 |
| Cluckbox Ltd | Hospitality | 2025 |
| Cludive Ltd | Information & communication | 2022 |
| Clue Finders Ltd | Arts & recreation | 2014 |
| Clutch and MOT Centre Kensington Limited | Wholesale & retail | 2023 |