| Cyber Technologies Ltd | Information & communication | 2011 |
| Cybergold UK Limited | Manufacturing | 1997 |
| Cyberstore Ltd | Wholesale & retail | 2025 |
| Cyborg's Wife Productions Limited | Information & communication | 2017 |
| Cybrix Systems Ltd | Information & communication | 2017 |
| Cygnus Teaching School Alliance Limited | Education | 2015 |
| Cymon Limited | Information & communication | 2014 |
| Cynosure Holding Ltd | Education | 2023 |
| CYR Data Ltd | Extraterritorial | 2021 |
| D & a Plumbing and Heating Ltd | Construction | 2012 |
| D & D Clutches Limited | Wholesale & retail | 2003 |
| D & M Sales Limited | Extraterritorial | 1992 |
| D & S Tool Hire Ltd | Administrative & support | 2016 |
| D B & C Consultancy Limited | Professional & scientific | 2016 |
| D C Comms Limited | Construction | 2016 |
| D Coyle Repairs Ltd | Manufacturing | 2025 |
| D Doyle Ltd | Construction | 2024 |
| D E Car Sales Ltd | Wholesale & retail | 2026 |
| D F E Catering Ltd | Hospitality | 2018 |
| D F Edwards Ltd | Administrative & support | 2013 |
| D G W Tool Making Ltd | Professional & scientific | 2014 |
| D J J Associates Limited | Professional & scientific | 2004 |
| D J Lewis Limited | Construction | 2004 |
| D K Carpentry & Construction Limited | Construction | 2024 |
| D Wiggins Services Ltd | Transport & logistics | 2003 |
| D&A Commercial Property Development Company Limited | Construction | 2026 |
| D&A Residential Property Development Company Limited | Construction | 2026 |
| D&A Welding Limited | Manufacturing | 2017 |
| D&E Facility Ltd | Administrative & support | 2018 |
| D&I Cooling Refrigeration Limited | Manufacturing | 2025 |
| D&N Software Solutions Ltd | Information & communication | 2019 |
| D&V Nuthall Ltd | Professional & scientific | 2013 |
| D. Brown & Co Building and Carpentry Ltd | Construction | 2024 |
| D. C. Products Limited | Manufacturing | 1989 |
| D.A.R. Management Ltd. | Wholesale & retail | 1993 |
| D.C. Site Services Limited | Administrative & support | 1993 |
| D.G Decorators (Middlesex) Ltd | Construction | 2022 |
| D.K.S Automotive Consulting Ltd | Administrative & support | 2014 |
| D.L.F Property Partners Ltd | Real estate | 2024 |
| D.R.J. Engineering Company Limited | Manufacturing | 1977 |
| D.W. Mead Construction Ltd | Construction | 2019 |
| D.W.Silver Construction Limited | Construction | 2019 |
| D21T Limited | Information & communication | 2015 |
| D2D Security Services Limited | Administrative & support | 2025 |
| D2R Windows Ltd | Construction | 2023 |
| D5-SAM Limited | Wholesale & retail | 2024 |
| DA Poetry JAM CIC | Arts & recreation | 2025 |
| DA Property and Land Limited | Real estate | 2019 |
| DA Realty Limited | Real estate | 2016 |
| DA Rocha Services Ltd | Wholesale & retail | 2020 |
| DA Silva’S Railway Ltd | Construction | 2025 |
| DA Totteridge Developments Ltd | Real estate | 2024 |
| DAD Developments NO 1 Ltd | Real estate | 2021 |
| DAD Developments NO 2 Ltd | Construction | 2023 |
| DAD Developments NO 3 Ltd | Real estate | 2023 |
| DAD Developments NO 4 Ltd | Construction | 2023 |
| DAD Homes Ltd | Real estate | 2015 |
| DAD Homes NO 1 Ltd | Real estate | 2023 |
| Dadyal Global Ltd | Wholesale & retail | 2026 |
| Daedalus Consulting Solutions Ltd | Professional & scientific | 2022 |
| Daevisha Properties Limited | Real estate | 2025 |
| Dafen Petrophysics Limited | Professional & scientific | 2022 |
| Daft DAD Publishing Limited | Information & communication | 2020 |
| Daicrochet Ltd | Wholesale & retail | 2025 |
| Daipop Consultancy Limited | Professional & scientific | 2022 |
| Daisychain Recruitment Limited | Administrative & support | 2008 |
| Dakang Wellbeing Ltd | Health & social care | 2022 |
| Dakar Properties Limited | Real estate | 2016 |
| Daley Sons & Co. Ltd | Real estate | 2026 |
| Dama GRP Ltd | Construction | 2025 |
| Damandi Ltd | Real estate | 2025 |
| Damar Signs Limited | Manufacturing | 2015 |
| Damaris Autos Ltd | Wholesale & retail | 2021 |
| Damecorte Ltd | Professional & scientific | 2025 |
| Damian Caviar Limited | Agriculture & fishing | 2023 |
| Damian Man&Van Ltd | Transport & logistics | 2024 |
| DAN & JOE Cars Ltd | Administrative & support | 2025 |
| DAN ROE Limited | Arts & recreation | 2011 |
| DAN Williams Ltd | Information & communication | 2019 |
| DAN Wise Creative Ltd | Information & communication | 2009 |
| Danajo & Company Limited | Professional & scientific | 2007 |
| Dandelion Business Support Ltd | Administrative & support | 2022 |
| Dandelion Publishing Limited | Extraterritorial | 2015 |
| Dane Cleaning Service Limited | Administrative & support | 2025 |
| Danes House Limited | Real estate | 2015 |
| Dango Logistics Ltd | Transport & logistics | 2021 |
| Daniel George Ltd | Construction | 2019 |
| Daniel Restoration Ltd | Construction | 2024 |
| Daniel White Electrical Ltd | Construction | 2021 |
| Danmac Kitchens and Bathrooms Limited | Construction | 2019 |
| Danny Clifford Productions Ltd | Arts & recreation | 2017 |
| Dansak Zone UK Ltd | Hospitality | 2019 |
| Dany G Contractors Ltd | Construction | 2024 |
| DAR Precision Motors Ltd | Wholesale & retail | 2025 |
| Darcan Ltd | Wholesale & retail | 2017 |
| Dark Panda Retail Limited | Wholesale & retail | 2025 |
| Dark Skin Beauty Ltd | Information & communication | 2022 |
| Darlinghurst Holdings Ltd | Real estate | 2019 |
| Darmaz Delivery Limited | Transport & logistics | 2013 |
| Daro-Pharm Ltd | Wholesale & retail | 2009 |