| Customs IX UK Ltd | Information & communication | 2024 |
| Cutlers Road Management Company Limited | Real estate | 1997 |
| Cutting View Construction Ltd | Construction | 2023 |
| CVL PR & Communications Ltd | Professional & scientific | 2026 |
| CW Wellbeing Limited | Health & social care | 2022 |
| Cwjv Consulting Limited | Professional & scientific | 2020 |
| CWL Pipework Services Ltd | Construction | 2025 |
| Cwssp Ltd | Other services | 2025 |
| Cyan Care Limited | Administrative & support | 2025 |
| Cyber Management Consulting Limited | Information & communication | 2017 |
| Cyclamen Limited | Health & social care | 2018 |
| Cycle Evolutions Ltd | Wholesale & retail | 2026 |
| Cyrec Ltd | Administrative & support | 2020 |
| Czap Ltd | Construction | 2025 |
| D & a Consultants (Essex) Ltd | Professional & scientific | 2015 |
| D & H Editions Limited | Administrative & support | 2015 |
| D & J Building Solutions Ltd | Households | 2019 |
| D & J Inns Ltd | Hospitality | 2017 |
| D & M Rhodes Building Contractors Ltd | Construction | 2019 |
| D & S Barbers Limited | Other services | 2012 |
| D & S Chlorination Services Limited | Energy | 2016 |
| D C Window Cleaning Limited | Administrative & support | 2018 |
| D K Cleaning Services Ltd | Other services | 2012 |
| D L Steel Fabrications Limited | Manufacturing | 1997 |
| D L Trees and Gardens Ltd | Agriculture & fishing | 2018 |
| D Northwood Properties Ltd | Real estate | 2023 |
| D R HO Consultancy Limited | Professional & scientific | 2012 |
| D R Management (London) Ltd | Professional & scientific | 2015 |
| D R Timber Ltd | Transport & logistics | 2003 |
| D Reed (Essex) Ltd | Information & communication | 2015 |
| D Shaw Financial Services Limited | Professional & scientific | 2020 |
| D Terret Ltd | Other services | 2020 |
| D V Management Limited | Hospitality | 2017 |
| D Weaver Builders Limited | Construction | 2018 |
| D&D Global Support Ltd | Wholesale & retail | 2021 |
| D&G Construction Enterprises Ltd | Construction | 2025 |
| D&H Living Limited | Wholesale & retail | 2014 |
| D&I Products Ltd | Wholesale & retail | 2018 |
| D&M Trans Ltd | Transport & logistics | 2020 |
| D&S Partners Limited | Real estate | 2023 |
| D'Silva Education Consultants Ltd | Education | 2012 |
| D-Fly Design Ltd | Wholesale & retail | 2019 |
| D. & a. Media Limited | Wholesale & retail | 2000 |
| D.B.J. (Woodford) Limited | Construction | 1974 |
| D.O.C Autos Limited | Manufacturing | 2017 |
| D.Pop Tiling Limited | Construction | 2021 |
| D.S.Rose Ltd | Construction | 2026 |
| D2C Management Solutions Ltd | Professional & scientific | 2012 |
| D2D Timber Ltd | Wholesale & retail | 2023 |
| Daads Ltd | Real estate | 2020 |
| Dadzie Limited | Other services | 2015 |
| Dagenham Demolition Ltd | Construction | 2020 |
| Dagenham Tyre Centre Ltd. | Wholesale & retail | 2003 |
| Dagwood Holdings Limited | Financial services | 2025 |
| Daiana’S Consultancy Ltd | Professional & scientific | 2023 |
| Daimer Industrial Supplies Ltd | Wholesale & retail | 2017 |
| Dale Services Contracts Ltd | Construction | 2005 |
| Dalectronics Limited | Energy | 2015 |
| Dalygray Mechanical Limited | Construction | 2012 |
| Damae Ltd | Wholesale & retail | 2019 |
| Damon Blaq Consulting Ltd | Real estate | 2025 |
| DAN Selo-Ojeme Healthcare Limited | Health & social care | 2011 |
| DAN Wright Fascia Limited | Construction | 2025 |
| Danaj Ltd | Construction | 2014 |
| Dancore Limited | Information & communication | 2025 |
| Dane Capital Limited | Administrative & support | 2026 |
| Daniel Automotive Limited | Wholesale & retail | 2018 |
| Daniel Bryant Hair Care Centre Limited | Other services | 2002 |
| Daniel Desmond Properties Limited | Real estate | 2016 |
| Daniel Franses Ltd. | Wholesale & retail | 2018 |
| Daniel James Capital Limited | Real estate | 2025 |
| Daniel James Chelmsford Ltd | Construction | 2024 |
| Daniel James Developments London Limited | Construction | 2016 |
| Daniel James Group Limited | Financial services | 2019 |
| Daniel James Housing Limited | Construction | 2024 |
| Daniel James Investments London Limited | Construction | 2019 |
| Daniel James Projects Limited | Construction | 2023 |
| Danielle’S Aesthetics Limited | Other services | 2022 |
| Daniyals Empire Ltd | Hospitality | 2025 |
| Danny Wilkey Limited | Professional & scientific | 2020 |
| Dansons Britain Limited | Wholesale & retail | 2021 |
| Danwrights.Com Ltd | Professional & scientific | 2020 |
| Dany Griffiths Limited | Other services | 2017 |
| Dapao GAR Ltd | Administrative & support | 2011 |
| DAR Managing Agencies Limited | Financial services | 2024 |
| Darian Innovation Agency Ltd | Information & communication | 2025 |
| Darke Safety Solutions Ltd | Professional & scientific | 2023 |
| Darren Newson Electrical Limited | Administrative & support | 2015 |
| Dasag Property Services Ltd | Real estate | 2025 |
| Dasilver Empire UK Ltd | Administrative & support | 2024 |
| Data and Digital Ltd | Information & communication | 2023 |
| Data Razi Limited | Information & communication | 2021 |
| Database Integrations Ltd | Information & communication | 2025 |
| Datacad Solutions UK Limited | Information & communication | 2016 |
| Datacryption Ltd | Information & communication | 2013 |
| Datchet Volunteers CIC | Health & social care | 2022 |
| Datefine Limited | Professional & scientific | 1993 |
| Dave Howard's Cleaning Services Ltd | Other services | 2006 |
| Davencroft Engineering Limited | | 1976 |
| Davenport QS Ltd | Administrative & support | 2010 |