| Cake Junkee Ltd | Wholesale & retail | 2021 |
| Cakebae London Limited | Hospitality | 2023 |
| Cakebox Creative Ltd | Information & communication | 2008 |
| Cakes and Bakes Luton Limited | Wholesale & retail | 2025 |
| Cakes by Aleina Ltd | Manufacturing | 2023 |
| Cakolli Property Ltd | Real estate | 2023 |
| Caldeira Associates Limited | Other services | 2012 |
| Caleb Consultants Ltd | Professional & scientific | 2010 |
| Caleb Properties Ltd | Real estate | 2025 |
| Cali Transport Limited | Transport & logistics | 2018 |
| Calibre LDN Limited | Wholesale & retail | 2025 |
| Calin Transport Ltd | Transport & logistics | 2019 |
| Calita Nutra Ltd | Manufacturing | 2020 |
| Call OUT Tyres Ltd | Wholesale & retail | 2024 |
| CALL2CARE Solutions Ltd | Administrative & support | 2022 |
| Callis Fish Ltd | Wholesale & retail | 2025 |
| Callum Repper Limited | Health & social care | 2016 |
| Camberwell Hospitality Ltd | Hospitality | 2025 |
| Camborne Chippy Limited | Hospitality | 2018 |
| Cambridge Business Research Limited | Administrative & support | 2009 |
| Cambridge Center of Analytics Limited | Education | 2023 |
| Cambridge Edge Limited | Information & communication | 2020 |
| Camden Hotel Limited | Hospitality | 2025 |
| Camelia Cleaning Services Ltd | Administrative & support | 2025 |
| Camelot Asset Management Ltd | Real estate | 2020 |
| Cameron Whyte Limited | Construction | 2020 |
| Camp Woodhall Ltd | Health & social care | 2015 |
| Campbell Care Group Ltd | Health & social care | 2025 |
| Campo Healthcare Limited | Health & social care | 2016 |
| Campoli Presti Ltd | Wholesale & retail | 2011 |
| Camrasonic Limited | Extraterritorial | 1984 |
| Camsten Construction Limited | Construction | 2019 |
| Camus Labs Ltd | Professional & scientific | 2025 |
| Cana Capernaum Limited | Transport & logistics | 2025 |
| Canadian Construction Limited | Construction | 2018 |
| Canam Compliance Limited | Administrative & support | 2019 |
| Canam Construction Ltd | Construction | 1998 |
| Canam Ltd | Construction | 2006 |
| Canary Consultancy Essex Ltd | Professional & scientific | 2025 |
| Canary Wharf Consult Limited | Education | 2025 |
| Candela VR CIC | Wholesale & retail | 2023 |
| Canham Building Services Ltd | Construction | 2009 |
| Cannajuana Ltd | Wholesale & retail | 2020 |
| Cannons Wood FC Ltd | Arts & recreation | 2021 |
| Cantaloop Fitness Ltd | Arts & recreation | 2024 |
| Canvas & Key Ltd | Hospitality | 2025 |
| CAP Clean Ltd | Administrative & support | 2022 |
| Cape (Electrical & Mechanical) Holdings Ltd | Construction | 2019 |
| Cape (Electrical & Mechanical) Ltd. | Construction | 2002 |
| Capernaum Group Limited | Financial services | 2016 |
| Capernaum Life Ltd | Health & social care | 2024 |
| Capital 1ST Electrical Ltd | Construction | 2015 |
| Capital 2 Properties Ltd | Construction | 2025 |
| Capital Build Construction Ltd | Construction | 2026 |
| Capital Calibration Services Limited | Professional & scientific | 2002 |
| Capital Commercial Transport Ltd | Transport & logistics | 2022 |
| Capital Construction Solutions Ltd | Water & waste | 2021 |
| Capital Invest Ltd | Financial services | 2024 |
| Caprani Holdings Limited | Wholesale & retail | 2015 |
| Capricorn Freeholds Limited | Real estate | 2011 |
| Capstick Dale & Partners Solicitors Ltd | Professional & scientific | 2020 |
| Capstick Dale Management Services Ltd | Real estate | 2015 |
| Capstick-Dale LLP | | 2010 |
| Capstone Services Ltd | Construction | 2019 |
| Captain Cares Limited | Health & social care | 2016 |
| Capthorne Properties Limited | Real estate | 2022 |
| Capturefour Limited | Information & communication | 2011 |
| Car City Limited | Wholesale & retail | 2022 |
| Car Clinic Group Ltd | Wholesale & retail | 2025 |
| Car Drift Ltd | Wholesale & retail | 2024 |
| Car ECU Solutions Ltd | Wholesale & retail | 2021 |
| Car Portal Ltd | Wholesale & retail | 2025 |
| Car Sales Network Limited | Wholesale & retail | 1995 |
| Car Sales Rainham Ltd | Wholesale & retail | 2017 |
| Car-Gone Limited | Transport & logistics | 2024 |
| Carbon IT Limited | Information & communication | 2001 |
| Carbon Performance Ltd | Manufacturing | 2026 |
| Carbon Pro Clean Ltd | Administrative & support | 2023 |
| Carbon Productions Ltd | Information & communication | 2021 |
| Card Payment Gateway Ltd | Other services | 2022 |
| Card Transact Limited | Financial services | 2016 |
| Cardcore Collectables Limited | Wholesale & retail | 2025 |
| Cardinal Move Ltd | Wholesale & retail | 2023 |
| Care and Care BG Ltd | Health & social care | 2022 |
| Care and Cure Physio Clinic Ltd | Other services | 2025 |
| Care Crown Services Limited | Health & social care | 2024 |
| Care First Care Ltd | Health & social care | 2022 |
| Care Home Support Services Limited | Administrative & support | 2019 |
| Care KIT 4U Ltd | Wholesale & retail | 2025 |
| Care Share Home Care Ltd | Health & social care | 2024 |
| Care Spark Limited | Professional & scientific | 2024 |
| Care Support Community Services Ltd | Health & social care | 2023 |
| Care Workers Union Ltd | Health & social care | 2021 |
| Career Crafters Digital Solutions Ltd | Education | 2026 |
| Career Deal Ltd | Education | 2022 |
| Career Path Limited | Administrative & support | 2025 |
| Career Vision (Global) Limited | Professional & scientific | 2002 |
| Caregig Limited | Information & communication | 2024 |
| Carehome London Limited | Health & social care | 2020 |
| Careway Transport Services Limited | Transport & logistics | 2026 |