| Claudiu Distribution Ltd | Transport & logistics | 2018 |
| Claverdon Carz Limited | Wholesale & retail | 2025 |
| Clavius Tech Limited | Manufacturing | 2023 |
| Claw Kingdom Nottingham Ltd | Arts & recreation | 2026 |
| Clawozium Ltd | Wholesale & retail | 2023 |
| Clawtidedecor Ltd | Wholesale & retail | 2025 |
| Clay Civil Consulting Limited | Professional & scientific | 2022 |
| Clay Studio Global Ltd | Professional & scientific | 2025 |
| Claycom Ltd | Professional & scientific | 2018 |
| Clayden Financial Planning Limited | Financial services | 2003 |
| Clayden FP Holdings Limited | Financial services | 2014 |
| Claydon Management (Leopards View) Limited | Households | 1994 |
| Claymore Advisory Group Ltd | Professional & scientific | 2023 |
| Clayton Equipment Limited | Manufacturing | 2004 |
| Clayton Solicitors Limited | Professional & scientific | 2016 |
| CLB JIN ZHU Limited | Administrative & support | 2011 |
| CLC Car Keys Ltd | Wholesale & retail | 2024 |
| CLC Developments (Midlands) Ltd | Construction | 2018 |
| CLC Law Limited | Professional & scientific | 2025 |
| CLC Online Learning Ltd | Education | 2023 |
| Cleaa Ltd | Real estate | 2025 |
| Clean & Cleanse Ltd | Administrative & support | 2025 |
| Clean & Co. Services Limited | Administrative & support | 2025 |
| Clean & Green Solutions Ltd | Transport & logistics | 2025 |
| Clean & Transport Limited | Administrative & support | 2024 |
| Clean Air International Ltd | Professional & scientific | 2020 |
| Clean ALL (Windows) Limited | Administrative & support | 2007 |
| Clean and Perfection Ltd | Administrative & support | 2020 |
| Clean Bill Corporation Ltd | Real estate | 2022 |
| Clean Bill Limited | Real estate | 2006 |
| Clean Bill Management Ltd | Professional & scientific | 2013 |
| Clean by Mide Limited | Administrative & support | 2025 |
| Clean City Cleaners Ltd | Administrative & support | 2025 |
| Clean Clean Limited | Other services | 2005 |
| Clean Crew UK Ltd | Administrative & support | 2025 |
| Clean CUT Halal Meat Ltd | Wholesale & retail | 2023 |
| Clean EAR Clinic Ltd | Health & social care | 2026 |
| Clean Edge Facilities Ltd | Administrative & support | 2025 |
| Clean Edges Consultancy Ltd | Information & communication | 2021 |
| Clean Essence Ltd | Administrative & support | 2025 |
| Clean Express Services Ltd | Administrative & support | 2025 |
| Clean Growth Ltd | Professional & scientific | 2025 |
| Clean Hands Cleaners Ltd | Other services | 2018 |
| Clean Hearing Ltd | Wholesale & retail | 2021 |
| Clean N Tidy Ltd | Administrative & support | 2021 |
| Clean Soul Ltd | Construction | 2025 |
| Clean Squares Limited | Administrative & support | 2019 |
| Clean Stock Limited | Wholesale & retail | 2019 |
| Clean With Elle Ltd | Administrative & support | 2024 |
| Clean World Birmingham Ltd | Other services | 2018 |
| Clean-Innovations Services Ltd | Construction | 2019 |
| CLEAN2GGO Limited | Administrative & support | 2019 |
| Cleanbody Limited | Wholesale & retail | 2025 |
| Cleancare House Limited | Real estate | 2007 |
| Cleancare Laundry Limited | Other services | 2011 |
| Cleancare Workwear Limited | Other services | 2007 |
| Cleanchoice Construction Ltd | Construction | 2025 |
| Cleanco Services Ltd | Administrative & support | 2016 |
| Cleancurve Connect Ltd | Energy | 2022 |
| Cleaner Samuel Ltd | Administrative & support | 2024 |
| Cleangreen Ltd | Arts & recreation | 2003 |
| Cleaning 4U Solutions Limited | Administrative & support | 2022 |
| Cleaning and Catering Supplies (CCS) Ltd | Wholesale & retail | 2010 |
| Cleaning Conservation Technologies Limited | Administrative & support | 2013 |
| Cleaning Force UK Ltd | Administrative & support | 2009 |
| Cleaning Global Limited | Administrative & support | 2026 |
| Cleaning Nationwide Ltd | Administrative & support | 2020 |
| Cleaning RAG Supply Co Limited | Wholesale & retail | 1984 |
| Cleaning Services Dura Ltd | Administrative & support | 2020 |
| Cleaning Solutions 4 U Ltd | Administrative & support | 2024 |
| Cleaning Support Services Limited | Administrative & support | 2003 |
| Cleaning Top UP Limited | Administrative & support | 2026 |
| Cleaning Washing Service Ltd Ltd | Administrative & support | 2025 |
| Cleaning Whizz Ltd | Administrative & support | 2023 |
| Cleaning&House Industrial Ltd | Administrative & support | 2024 |
| Cleanmira Solutions Ltd | Information & communication | 2025 |
| Cleannest Realty Limited | Administrative & support | 2024 |
| Cleanova Services Limited | Administrative & support | 2018 |
| Cleanright Solutions Ltd | Administrative & support | 2024 |
| Cleanroom Design and Construction Ltd | Health & social care | 2022 |
| Cleansed Vision Limited | Wholesale & retail | 2013 |
| Cleanserve Limited | Administrative & support | 2013 |
| Cleansirius Limited | Wholesale & retail | 2025 |
| Cleanutopia Ltd | Administrative & support | 2025 |
| Clear and Black Ltd | Wholesale & retail | 2020 |
| Clear Balance Ltd | Professional & scientific | 2023 |
| Clear Business Services Ltd | Professional & scientific | 2014 |
| Clear Choice Care Solutions Limited | Health & social care | 2016 |
| Clear Choice Cars Ltd | Wholesale & retail | 2025 |
| Clear Clean Ltd | Administrative & support | 2019 |
| Clear Competitions Ltd | Arts & recreation | 2026 |
| Clear Crystal Limited | Administrative & support | 2026 |
| Clear CUT Nations and Regions Limited | Information & communication | 1996 |
| Clear CUT Painting Ltd | Construction | 2024 |
| Clear Housing Ltd | Hospitality | 2016 |
| Clear Insights Consulting Limited | Extraterritorial | 2012 |
| Clear Mind Enterprise Ltd | Wholesale & retail | 2023 |
| Clear Mortgage and Protection Solutions Ltd | Financial services | 2005 |
| Clear OUT Stores Ltd | Wholesale & retail | 2025 |
| Clear Path Housing Ltd | Real estate | 2020 |