| C.A.L.T Enterprises Limited | Water & waste | 2013 |
| C.B Discos and Events Ltd. | Administrative & support | 2017 |
| C.K. Cargo Limited | Transport & logistics | 1985 |
| C.S. Auto Limited | Wholesale & retail | 2014 |
| C.W. Security Systems Ltd | Administrative & support | 2010 |
| C10 Propco Ltd | Financial services | 2026 |
| C2C Aero Limited | Wholesale & retail | 2021 |
| C4H Developments Ltd | Construction | 2021 |
| CAA International Limited | Public administration | 2000 |
| Cabline Gatwick Limited | Administrative & support | 2015 |
| CAE Aviation Academy (Oxford) Ltd | Education | 2007 |
| CAE Training & Services UK Ltd | Transport & logistics | 1998 |
| Cafe Hub Ltd | Hospitality | 2023 |
| Cahill-Property Ltd | Real estate | 2022 |
| Caines Couriers Limited | Transport & logistics | 2024 |
| Caines Services Limited | Professional & scientific | 2018 |
| Cake World by Georgy Ltd | Manufacturing | 2021 |
| Cakes by D&M Limited | Manufacturing | 2012 |
| Cala Medical Aesthetics Ltd | Health & social care | 2026 |
| Cali Creations Floral Designs Ltd | Other services | 2022 |
| Calka Software Ltd | Information & communication | 2018 |
| Call CAB Ltd | Wholesale & retail | 2021 |
| Call ME YVE Ltd | Wholesale & retail | 2024 |
| Calm Cottage Ltd | Professional & scientific | 2024 |
| Cambert Cleaning Services Ltd | Professional & scientific | 2010 |
| Cambourne Dental Care Limited | Health & social care | 2011 |
| Cambridge Analytical Group Limited | Extraterritorial | 1985 |
| Camelot Chilled Foods Ltd | Wholesale & retail | 1997 |
| Cameron Rogers Coaching Ltd | Arts & recreation | 2023 |
| Campbell Pest Control Ltd | Administrative & support | 2022 |
| Campbellscleaning Ltd | Administrative & support | 2025 |
| Campbellwood Cleaning Solutions Ltd | Administrative & support | 2021 |
| Canon Business Centre SOS Limited | Extraterritorial | 2023 |
| Canon Medical Systems Limited | Manufacturing | 1970 |
| Canvas Tent Hire Ltd | Administrative & support | 2025 |
| Capabilix Limited | Professional & scientific | 2025 |
| Capital Cars Sussex Ltd | Transport & logistics | 2022 |
| Capital Garage Doors Limited | Construction | 1978 |
| Capital Legal Limited | Wholesale & retail | 2024 |
| Capri Cars Gatwick Limited | Transport & logistics | 2022 |
| CAPTIV8 Solutions Limited | Administrative & support | 2014 |
| Car Legacy Ltd | Wholesale & retail | 2024 |
| Car World London Ltd | Wholesale & retail | 2017 |
| Cara's Commercial Cleaning Services Ltd | Administrative & support | 2022 |
| Caractere Ltd | Hospitality | 2018 |
| Caravaggio & Contemporary Ltd | Education | 2022 |
| Carbonseries Ltd | Information & communication | 2024 |
| Cardinal Asset Management Services Limited | Professional & scientific | 2017 |
| Cardinal Engineering Limited | Construction | 2012 |
| Cardinal Estate Services Ltd | Real estate | 2023 |
| Care and Mobility Specialist Services Ltd | Professional & scientific | 2025 |
| Care Givers Global UK Limited | Administrative & support | 2022 |
| Care Moments Healthcare Ltd | Health & social care | 2020 |
| Care Plus Housing Ltd | Health & social care | 2024 |
| Care Spirit Limited | Health & social care | 2018 |
| Careena Tea & Commodities Limited | Wholesale & retail | 2015 |
| Careforthemcare Limited | Real estate | 2020 |
| Carent Ltd | Information & communication | 2024 |
| Carephil Limited | Health & social care | 2011 |
| Carers Nationwide Limited | Administrative & support | 2016 |
| Careteam Services Ltd | Administrative & support | 2020 |
| Cargan Services Limited | Construction | 2024 |
| Carillon Dental Care Ltd | Health & social care | 2013 |
| Carissa Homes Ltd | Real estate | 2025 |
| Carlynn Property Investments Limited | Real estate | 2026 |
| Carnivore Industries Ltd | Wholesale & retail | 2025 |
| Carpcharge Ltd | Wholesale & retail | 2025 |
| Carr Taylor Wines Limited | Manufacturing | 2000 |
| Carreon Limited | Real estate | 2025 |
| Carrivo Global Careers Ltd | Administrative & support | 2025 |
| Carry Go Logistics and Equipment Ltd | Transport & logistics | 2025 |
| Carse I.T Services Limited | Information & communication | 2011 |
| Carson Maintenance Company Ltd | Construction | 2025 |
| Carter Thorne Carpets and Flooring 2018 Ltd | Wholesale & retail | 2018 |
| Carthub Ltd | Wholesale & retail | 2025 |
| Carvalho Holdings Limited | Financial services | 2020 |
| Cascade Swimming Pools Limited | Wholesale & retail | 1990 |
| Cash Your Vintage Ltd | Wholesale & retail | 2025 |
| Casp 33B Limited | Real estate | 2016 |
| Castle Servicing (Reigate) Ltd | Wholesale & retail | 2014 |
| Castlebrowne Services Limited | Construction | 2025 |
| Castlefield House Limited | Professional & scientific | 2012 |
| Castro's Short Stays Ltd | Real estate | 2025 |
| Catalin Aurelian Ltd | Construction | 2023 |
| Catalyst Integration Services Ltd | Professional & scientific | 2023 |
| Catbloo Trading Limited | Wholesale & retail | 2006 |
| Catering Post Holdings Ltd | Real estate | 2026 |
| CB GAS & OIL Heating Ltd | Construction | 2022 |
| CBA Aviation Limited | Education | 2016 |
| Cbliss Ltd | Wholesale & retail | 2024 |
| CC Auto Limited | Wholesale & retail | 2021 |
| CC Properties Holding Limited | Real estate | 2025 |
| CCI Gatwick Ltd | Construction | 1996 |
| Ccls South Ltd | Construction | 2015 |
| CCS Integration Limited | Construction | 2021 |
| CCS23 Ltd | Construction | 2015 |
| CDP Solutions Limited | Information & communication | 2002 |
| Cea's Quality Ltd | Financial services | 2025 |
| Cecil Macdonald & Co Limited | Wholesale & retail | 1947 |
| Cedar House Securities Limited | Construction | 1986 |