| Crescendo (UK) Limited | Professional & scientific | 2014 |
| Crescent Marquee Ltd | Administrative & support | 2024 |
| Crestline Capital Ltd | Financial services | 2025 |
| CRH Scaffolding Ltd | Construction | 2025 |
| Crinford Limited | Households | 1991 |
| Cris Maintenance Ltd | Construction | 2019 |
| Cristina Kruppa Interpreter Ltd | Administrative & support | 2007 |
| Crmc Construction Ltd | Construction | 2023 |
| Croft Productions Ltd | Information & communication | 2025 |
| Cromwell Electrical Management Ltd | Construction | 2024 |
| Cronus Limited | Real estate | 1995 |
| Crossfield ST Developments Ltd | Construction | 2020 |
| Crown Aids Limited | Administrative & support | 2026 |
| Crown and Cushion SE1 Limited | Hospitality | 2025 |
| Crown Beauty Ltd | Other services | 2011 |
| Crown Digital Limited | Information & communication | 2015 |
| Crown House Projects Limited | Construction | 2013 |
| Crowning Glory Limited | Professional & scientific | 2016 |
| Croydon Courier Service CCS Ltd | Transport & logistics | 2017 |
| Crux West Ltd | Professional & scientific | 2022 |
| CRW Electrical Limited | Construction | 2011 |
| Cryoskincare Ltd | Other services | 2020 |
| Crystalcube Enterprises Limited | Wholesale & retail | 2013 |
| Csfeq Limited | Administrative & support | 2024 |
| Csheer Group Ltd | Financial services | 2025 |
| CTA Housing Consultants Limited | Administrative & support | 2023 |
| Ctca UK Limited | Education | 2018 |
| CTM PM Limited | Construction | 2017 |
| Ctrl Services Ltd | Administrative & support | 2017 |
| Cubewing Holdings Limited | Financial services | 2018 |
| Cubewing Systems Limited | Wholesale & retail | 1987 |
| Cuinntech Limited | Professional & scientific | 2017 |
| CUP Full Productions Limited | Professional & scientific | 2019 |
| Current Direction Renewable Energy Ltd | Construction | 2022 |
| Curry House (Sidcup) Ltd | Hospitality | 2017 |
| Curry Mahal Sidcup Ltd | Hospitality | 2026 |
| Curtze Thompson Ltd | Hospitality | 2026 |
| Custom View Limited | Manufacturing | 2019 |
| Cutting Edge Decorators Ltd | Construction | 2026 |
| Cyberkix Limited | Administrative & support | 1996 |
| Cyrus House Limited | Households | 2021 |
| Cytrad Group Ltd | Financial services | 2000 |
| D & C Property Investment Limited | Real estate | 2022 |
| D & C Track Projects Limited | Construction | 2016 |
| D & R Roofing and Building Specialists Ltd. | Construction | 2010 |
| D and J Management Ltd | Hospitality | 2017 |
| D C Haulage (Kent) Limited | Administrative & support | 2016 |
| D J Russell Carpentry Limited | Construction | 2025 |
| D J Scoble Complete Services Limited | Construction | 2017 |
| D J Scoble Electrical Services Limited | Construction | 2024 |
| D Mace Electrical Limited | Construction | 2016 |
| D Powell Consulting Ltd | Financial services | 2023 |
| D R Recovery Ltd | Wholesale & retail | 2008 |
| D Russell Carpentry Limited | Construction | 2012 |
| D Spring Electrical Limited | Construction | 2018 |
| D U Services (QS) Ltd | Administrative & support | 2017 |
| D Wright Electricals Limited | Construction | 2007 |
| D&D Wildflower Homes Ltd | Real estate | 2026 |
| D&M Decor Service Ltd | Construction | 2023 |
| D&S Painters and Decorators Ltd | Construction | 2022 |
| D&S Properties (South East) Limited | Administrative & support | 2017 |
| D-Cipher Limited | Administrative & support | 2003 |
| D.B Dockers Taxis Limited | Transport & logistics | 2019 |
| D.M. Bass Investments Limited | Administrative & support | 1925 |
| D.S.A Consultancy Ltd | Health & social care | 2015 |
| D.Sh Drylining Ltd | Construction | 2018 |
| DA Plumbing and Mechanical Limited | Construction | 2015 |
| Daccan Limited | Professional & scientific | 2012 |
| Daemon Models Limited | Professional & scientific | 2025 |
| Dake Ltd | Real estate | 2019 |
| Daleby Marine Services Limited | Professional & scientific | 2011 |
| Dama Projects Ltd | Administrative & support | 2024 |
| Damage Genie Ltd | Construction | 2016 |
| DAN Seffens Design Limited | Professional & scientific | 2018 |
| Danaher Rail Management Ltd | Construction | 2021 |
| Danbea Ltd | Manufacturing | 2026 |
| Daniel Ventura Fitness Ltd | Other services | 2013 |
| Daniell Building Contractors Limited | Construction | 2011 |
| Daniell Construction Limited | Construction | 2016 |
| Danifab Ltd | Wholesale & retail | 2012 |
| Danny Ruta Consultancy Limited | Health & social care | 2019 |
| Dansku Productions Limited | Information & communication | 2013 |
| Danson Court Limited | Extraterritorial | 2004 |
| Danson Group Limited | Financial services | 2020 |
| Danson Park Bowls Consortium Limited | Arts & recreation | 1993 |
| Dantine Estates Limited | Real estate | 2022 |
| DANUT78MIHAI Ltd | Information & communication | 2025 |
| Dapa Home Ltd | Administrative & support | 2022 |
| Dapa Interiors Limited | Professional & scientific | 2018 |
| DAR Construction Ltd | Construction | 2025 |
| DAR Consulting Limited | Construction | 2021 |
| Darj Consulting Limited | Construction | 2025 |
| Dartford Car Hire Limited | Administrative & support | 2012 |
| Dasec Security Limited | Administrative & support | 2018 |
| Dash Decorations Limited | Construction | 2023 |
| Data Intouch Ltd | Professional & scientific | 2020 |
| Data Protect UK Limited | Professional & scientific | 2003 |
| Data Protect UK Properties Limited | Professional & scientific | 2015 |
| Datacom Management Limited | Information & communication | 2014 |
| Datacomms Engineering Ltd | Information & communication | 2021 |