| Computing Curriculum Solutions Ltd | Information & communication | 2016 |
| Concept Pundits Limited | Information & communication | 2025 |
| Conexx London Minicab Ltd | Transport & logistics | 2014 |
| Conquest Tech Solutions Ltd | Information & communication | 2015 |
| Consolor Limited | Manufacturing | 2006 |
| Cool Valley Limited | Construction | 2022 |
| Copain Ltd | Professional & scientific | 2025 |
| Corban Construction Ltd | Construction | 2022 |
| Cordial Chauffeur Service Ltd | Transport & logistics | 2024 |
| Corepulse AI Ltd | Information & communication | 2026 |
| Corporate Carriages of London Limited | Transport & logistics | 2009 |
| Cosic Ltd | Construction | 2016 |
| Costy Jerry Ltd | Transport & logistics | 2024 |
| COSTY191184 Ltd | Transport & logistics | 2022 |
| Cougar Couriers Holdings Limited | Financial services | 2021 |
| Cougar Couriers Limited | Transport & logistics | 1993 |
| Country Floors Ltd | Construction | 2020 |
| CPC Carpenter Ltd | Construction | 2017 |
| Crack on Construction Ltd | Construction | 2024 |
| Creative Movie Solutions Ltd | Information & communication | 2014 |
| Credent Property Management Ltd | Real estate | 2024 |
| CRH Transport Ltd | Construction | 2025 |
| Crislex Services Ltd | Construction | 2019 |
| Cristais Mistico Ltd | Wholesale & retail | 2025 |
| CRK Property Services Limited | Construction | 2014 |
| Crocus Landscapes Ltd | Administrative & support | 2017 |
| Cropmate Ltd | Agriculture & fishing | 2025 |
| Crown City Transfers Ltd | Transport & logistics | 2024 |
| Crown Management (Farnham Royal Ltd | Real estate | 2022 |
| Cruise Minibuses Limited | Transport & logistics | 2007 |
| CSK Driving School Ltd | Education | 2024 |
| Ctrc Community Interest Company | Health & social care | 2011 |
| Cugo Security Limited | Administrative & support | 2024 |
| CV Warehouse Limited | Administrative & support | 2023 |
| CWC Labour Services Ltd | Construction | 2025 |
| Cyndellar Limited | Financial services | 2024 |
| Cynerite Limited | Financial services | 2024 |
| D and P Sealants Limited | Construction | 2023 |
| D Procare Limited | Wholesale & retail | 2022 |
| D Rogers Building Services Limited | Construction | 2018 |
| D&A Enterprises Ltd | Professional & scientific | 2024 |
| D&D Deco Ltd | Construction | 2026 |
| D&L Transporters Ltd | Transport & logistics | 2018 |
| D&P Automoto Ltd | Wholesale & retail | 2021 |
| D'Costa Talent Solutions Ltd | Administrative & support | 2025 |
| D2D Company Private Limited | Professional & scientific | 2011 |
| DA Caribbean Kitchen Limited | Hospitality | 2023 |
| DA Green Ltd | Households | 2024 |
| Daakshi Vale UK Limited | Real estate | 2018 |
| Dabino Co Ltd | Manufacturing | 2026 |
| Dad's and Lad's Barber Ltd | Other services | 2018 |
| Dahir Transport and Logistics Ltd | Transport & logistics | 2025 |
| Daidi Ltd | Wholesale & retail | 2025 |
| Daman Osteopathy Ltd | Health & social care | 2024 |
| Daneka Limited | Wholesale & retail | 2024 |
| Daniel & SON Ltd | Construction | 2026 |
| Daniel Nsomi Global Limited | Professional & scientific | 2025 |
| Danpol Ltd | Administrative & support | 2016 |
| Danraph Haulage Limited | Transport & logistics | 2023 |
| Dansteco Ltd | Construction | 2024 |
| DAR AL OUD Ltd | Wholesale & retail | 2025 |
| Darp Distribution Ltd | Wholesale & retail | 2018 |
| Darvesh Ltd | Transport & logistics | 2017 |
| Dashmesh Accounting Limited | Professional & scientific | 2022 |
| Dav&Sam Trade Ltd | Wholesale & retail | 2019 |
| David and Brothers Import and Export Ltd | Other services | 2017 |
| David Michael MYO Myint Limited | Extraterritorial | 2024 |
| Davinder Constructions Ltd | Construction | 2022 |
| Davmark Limited | Information & communication | 1994 |
| Dazzleyoureyes Ltd | Wholesale & retail | 2017 |
| DBL Property Investments Ltd | Real estate | 2025 |
| DBR Industries Limited | Manufacturing | 2026 |
| DC Decorator Services Ltd | Construction | 2023 |
| DC Global Education Group Ltd | Education | 2026 |
| DDG Construction Ltd | Manufacturing | 2026 |
| DE Burgh Arms Ltd | Real estate | 2012 |
| DEE N ZEE Ltd | Other services | 2020 |
| Deeper Associates (London) Limited | Administrative & support | 2022 |
| Deeper Associates (Westminster) Limited | Administrative & support | 2022 |
| Deeptech Semiconductors Limited | Information & communication | 2025 |
| Define Care&Consulting Ltd | Health & social care | 2026 |
| Deluxe Airport Transfers Ltd | Transport & logistics | 2022 |
| Denbro Property Development Ltd | Construction | 2023 |
| Denilon Limited | Real estate | 2024 |
| Density AI Ltd. | Information & communication | 2023 |
| Density Group Ltd. | Information & communication | 2024 |
| Deol Properties Limited | Real estate | 2016 |
| Desi Bagpackers Limited | Administrative & support | 2025 |
| Desi Boys London Ltd | Wholesale & retail | 2020 |
| Desi Punch Ltd | Administrative & support | 2023 |
| Devzone Ltd | Information & communication | 2013 |
| DF Building Consultants Limited | Construction | 2026 |
| DGB Freight Ltd | Transport & logistics | 2021 |
| Dgff Ltd | Information & communication | 2025 |
| Dhaliwal Scaffolding & Roofing Ltd | Construction | 2016 |
| Dhillon Group of Homes Ltd | Real estate | 2025 |
| Dhillon Logistics Ltd | Transport & logistics | 2025 |
| Dhishum Technologies Ltd | Information & communication | 2015 |
| Dhrudi Ltd | Real estate | 2025 |
| Dial Tone Limited | Wholesale & retail | 2016 |