| Cybermind Tech Services UK Ltd | Information & communication | 2025 |
| Cybrotech Limited | Professional & scientific | 2004 |
| Cygnus Property Group Limited | Real estate | 2021 |
| CYP Electrical Ltd | Construction | 2026 |
| Cysa Ltd | Other services | 2017 |
| CYY Limited | Health & social care | 2008 |
| D & B Motorcycles Limited | Wholesale & retail | 2008 |
| D & DI Limited | Transport & logistics | 2018 |
| D & R Trading Limited | Professional & scientific | 2003 |
| D a M Real Estate Limited | Real estate | 2018 |
| D Cleaning Ltd | Other services | 2017 |
| D Goldstein & Co (Surveyor) | Real estate | 1972 |
| D J Rice Ltd | Information & communication | 2012 |
| D KAY Investments Ltd | Administrative & support | 2026 |
| D LUX Interior Designs Ltd | Real estate | 2022 |
| D M T Wholesale Limited | Wholesale & retail | 2008 |
| D S Edwards Limited | Health & social care | 2018 |
| D&D Utilities Ltd | Hospitality | 2023 |
| D&G Estates Ltd | Real estate | 2019 |
| D&P London Perfumes Ltd | Wholesale & retail | 2026 |
| D&P Property Rentals Ltd | Real estate | 2023 |
| D&S Associates (London) Limited | Construction | 2006 |
| D&V Limited | Financial services | 2023 |
| D. C. Dodd Motor Repairs Limited | Wholesale & retail | 2011 |
| D. Lewis Ltd | Wholesale & retail | 2011 |
| D.A.R Gardening Ltd | Administrative & support | 2026 |
| D.Blanks Transport Ltd | Transport & logistics | 2025 |
| D.Ostrin Limited | Real estate | 1957 |
| D.P. Home Interiors & Design Ltd | Construction | 2025 |
| D2 Real Estate Ltd | Real estate | 2026 |
| D2M Investments Ltd | Real estate | 2018 |
| Daain Ltd | Real estate | 2020 |
| Daana Limited | Wholesale & retail | 2025 |
| DAB Carpentry Ltd | Manufacturing | 2024 |
| Dabeli Holdings Ltd | Real estate | 2026 |
| Dabeli Rickmansworth Ltd | Real estate | 2026 |
| Dacia Felix Ltd | Hospitality | 2010 |
| Dacs Solutions Ltd | Construction | 2024 |
| DAD Logistics Ltd | Construction | 2019 |
| Daddy Works Limited | Construction | 2025 |
| Dadu Rail Services Ltd | Other services | 2016 |
| Daily Delights London Limited | Wholesale & retail | 2025 |
| Daily Mobility Ltd | Health & social care | 2010 |
| Dale Avenue Nursey Ltd | Other services | 2022 |
| Dalerina Ltd | Construction | 2024 |
| Dalforna Limited | Professional & scientific | 2026 |
| Dalina Properties Ltd | Real estate | 2018 |
| Dalina's UK- Ltd | Hospitality | 2024 |
| Dalru Limited | Real estate | 2025 |
| DAM Constructions Services Limited | Construction | 2015 |
| Damore Ventures Limited | Real estate | 2023 |
| Damzz Ltd | Arts & recreation | 2024 |
| DAN and Sons Electrical Ltd | Construction | 2023 |
| DAN Construction Ltd | Construction | 2018 |
| DAN Plumbing Construct Ltd | Manufacturing | 2023 |
| Dana Beauty Shop Ltd | Wholesale & retail | 2023 |
| Dana Professional Ltd | Wholesale & retail | 2025 |
| Dancers World Ltd | Wholesale & retail | 2009 |
| Dandunne Ltd | Real estate | 2025 |
| Dandylion Consulting Ltd | Real estate | 2015 |
| Daneput Limited | Real estate | 2025 |
| Danesh & Nielsen Ltd | Real estate | 2024 |
| Dani Daniel's Limited | Manufacturing | 2019 |
| Dani Handyman Services Ltd | Construction | 2025 |
| Daniel Film Finance Limited | Information & communication | 2014 |
| Daniel Guinchard Racing Ltd | Arts & recreation | 2021 |
| Danielipb Ltd | Manufacturing | 2026 |
| Danifabb Ltd | Transport & logistics | 2026 |
| Danimiha Ltd | Construction | 2019 |
| Dankbrook Limited | Real estate | 1998 |
| Danmar Construction Ltd | Construction | 2019 |
| Danny's Labours Limited | Construction | 2019 |
| DANNY21 Ltd | Construction | 2018 |
| Dannymar Contractors Ltd | Construction | 2017 |
| Dansk LLP | | 2008 |
| Dant Investments Limited | Real estate | 2024 |
| Dant Properties Limited | Real estate | 2000 |
| Dapersdesign Ltd | Professional & scientific | 2025 |
| DAR Driving Ltd | Transport & logistics | 2023 |
| Darcey Stevens Limited | Real estate | 2018 |
| Dario Drylining Ltd | Construction | 2018 |
| Darren James Design Ltd | Professional & scientific | 2012 |
| Darren MMA Limited | Arts & recreation | 2020 |
| Darryl Ingram Limited | Professional & scientific | 2011 |
| Darseld Limited | Professional & scientific | 2022 |
| Darvish (London) Properties Limited | Households | 2022 |
| DAS Haulage Ltd | Transport & logistics | 2014 |
| Dasa Capital Ltd | Financial services | 2022 |
| Dasa Concepts and Design Limited | Professional & scientific | 2024 |
| Dasa Consultants Ltd | Administrative & support | 2026 |
| Dasa Lettings Ltd | Real estate | 2019 |
| Dasa Properties Ltd | Real estate | 2016 |
| Dasa Services Ltd | Administrative & support | 2019 |
| Dasa Wholesale Ltd | Wholesale & retail | 2023 |
| Dashri Ltd | Hospitality | 2019 |
| Dasj Investments Limited | Real estate | 2018 |
| Data Decisions Limited | Information & communication | 2026 |
| Data Handyperson Ltd | Information & communication | 2024 |
| Dataal Limited | Wholesale & retail | 2014 |
| Datalytics Tech Limited | Information & communication | 2017 |