| Cubeix Investments Limited | Real estate | 2016 |
| Cubelogic Consulting Limited | Information & communication | 2010 |
| Cuffe Fabrication Services Limited | Manufacturing | 2025 |
| Cultural Awareness Ltd | Education | 2003 |
| Cunningham Design & Build Ltd | Construction | 2024 |
| Curative Medical Limited | Wholesale & retail | 2024 |
| Curious Kids Club Ltd | Education | 2024 |
| Curioux Limited | Information & communication | 2022 |
| Curiz Limited | Professional & scientific | 2018 |
| Curvy Kate Ltd | Wholesale & retail | 2009 |
| Custom Kitchen & Wardrobes Limited | Manufacturing | 2025 |
| Cwilson Enterprises Ltd | Professional & scientific | 2013 |
| Cyan Paradigm Limited | Professional & scientific | 2017 |
| Cyber Blue Limited | Information & communication | 2021 |
| Cyber IT Solutions Limited | Information & communication | 2018 |
| Cyber Spot UK Ltd | Wholesale & retail | 2024 |
| Cybersecure Technology Ltd | Information & communication | 2008 |
| Cyberst Limited | Information & communication | 2013 |
| Cybersystemscert Ltd | Information & communication | 2016 |
| Cycle Nest Properties Ltd | Real estate | 2025 |
| Cydney’S Aesthetics Ltd | Other services | 2019 |
| Cymabay UK, Ltd. | Professional & scientific | 2018 |
| Cyres Property Management Limited | Real estate | 2021 |
| D & a Landscape Gardening Limited | Administrative & support | 2018 |
| D & C West Limited | Real estate | 2020 |
| D & G Realty Ltd | Real estate | 2021 |
| D Komor Technology Ltd | Manufacturing | 2021 |
| D M B Services (Uxbridge) Ltd. | Other services | 2014 |
| D Meeking Ltd | Other services | 2011 |
| D Rigg Haulage Limited | Transport & logistics | 2010 |
| D Sidhu Consulting Limited | Professional & scientific | 2026 |
| D&C Perkins Properties Ltd | Real estate | 2016 |
| D&D Access London Ltd | Construction | 2023 |
| D&D Perkins Properties Ltd | Real estate | 2016 |
| D&T Perkins Properties Ltd | Real estate | 2016 |
| D&T West Limited | Real estate | 2026 |
| D-Dot Developments Ltd | Construction | 2019 |
| D. a. Building Ltd | Construction | 2016 |
| D. Blowers Limited | Transport & logistics | 1951 |
| D.K.V.D Decorating Limited | Construction | 2018 |
| D.M. Village Bakery Limited | Wholesale & retail | 2006 |
| D.S. Preston (Garages) Limited | Wholesale & retail | 1990 |
| D1 Hire Ltd | Administrative & support | 2024 |
| D4U Logistics Ltd | Wholesale & retail | 2023 |
| DA Creative Solutions Ltd | Education | 2017 |
| DA Management Services Ltd | Construction | 2015 |
| DA Silva Costa Ltd | Construction | 2022 |
| Daas Homes Ltd | Real estate | 2021 |
| DAB Property Investments Limited | Real estate | 2023 |
| Dachels.Com (UK) Ltd | Wholesale & retail | 2011 |
| DAG Properties (Warrington) Limited | Real estate | 2023 |
| Daiichi Sankyo UK Limited | Wholesale & retail | 1986 |
| Daily Eats Limited | Manufacturing | 2025 |
| Daily Enterprise Ltd | Wholesale & retail | 2024 |
| Daisy Rigging Ltd | Construction | 2023 |
| Daisybrook Limited | Health & social care | 1995 |
| Daivik Consultancy Limited | Other services | 2018 |
| DAJ Financial Services Ltd | Financial services | 2017 |
| Dajam Energy UK Ltd | Other services | 2017 |
| Dajojo Ltd | Extraterritorial | 2021 |
| Dak-Tech Ltd | Information & communication | 2015 |
| Dakanee Ltd | Wholesale & retail | 2025 |
| Dale Jester Lighting Ltd | Professional & scientific | 2013 |
| Dalehead Foods Limited | Extraterritorial | 1972 |
| Dalsons Property Management Limited | Real estate | 2019 |
| Dalton Solutions Ltd | Transport & logistics | 2021 |
| Daly Construction Services Ltd | Construction | 2017 |
| Damas Food Limited | Hospitality | 2018 |
| DAN Construct Cleaning Ltd | Administrative & support | 2026 |
| DAN Franciug Ltd | Transport & logistics | 2013 |
| DAN JR Transport Ltd | Transport & logistics | 2015 |
| DAN Williams Design Limited | Information & communication | 2016 |
| Danbar Solicitors Limited | Professional & scientific | 2013 |
| Dance Savoir Faire Ltd | Arts & recreation | 2013 |
| Daniel James (Furnishings) Limited | Manufacturing | 1975 |
| Daniel James Fabrics Limited | Wholesale & retail | 2007 |
| Daniel Logistic and Transport Ltd | Transport & logistics | 2021 |
| Daniel Vazquez Studio Limited | Professional & scientific | 2017 |
| Dantec Engineering Limited | Professional & scientific | 2018 |
| Danual’S Limited | Information & communication | 2022 |
| Daolytica Limited | Information & communication | 2025 |
| Daphne Court (Ealing) Residents Association Limited | Households | 1971 |
| DAR Imane Ltd | Wholesale & retail | 2026 |
| Daran Ltd | Professional & scientific | 2021 |
| Darcy's Cafe Limited | Hospitality | 2020 |
| Dardan Engineering Ltd | Professional & scientific | 2025 |
| Darhas Services &FM Ltd | Construction | 2023 |
| Dark Horse Real Estate Ltd | Real estate | 2023 |
| Darkskyefx Limited | Health & social care | 2026 |
| Darley Investments Ltd | Financial services | 2016 |
| Darlington Property Management Limited | Real estate | 2006 |
| Darragh Tierney Contracts Ltd | Construction | 2024 |
| Darren James Thorpe Ltd | Extraterritorial | 2024 |
| Darren Jordan Mechanical Labour Services Ltd | Administrative & support | 2017 |
| Darsh Pharmalink Limited | Professional & scientific | 2015 |
| Darsh Properties Ltd | Real estate | 2023 |
| Dartford Warbler Ltd | Construction | 2017 |
| Dartnel Freeholders Limited | Real estate | 2006 |
| Dartnel Management Limited | Real estate | 1974 |
| Darudoon Limited | Wholesale & retail | 2025 |