| CPP Denture Studio Limited | Administrative & support | 2007 |
| Crabb Appleby LLP | | 2004 |
| Crack the Pack Ltd | Wholesale & retail | 2025 |
| Cradle for Life International | Health & social care | 2004 |
| Craft and HUE Limited | Arts & recreation | 2024 |
| Craftsman & Blacksmith Ltd | Wholesale & retail | 2025 |
| Cramus Limited | Construction | 2015 |
| Crane Building Management Services Limited | Construction | 2012 |
| Cranham Garage Limited | Wholesale & retail | 2012 |
| CRANSTON33 Limited | Real estate | 2015 |
| Crate Boxes Limited | Wholesale & retail | 2024 |
| CRE Logistics Ltd | Transport & logistics | 2021 |
| CRE Transport Ltd | Transport & logistics | 2020 |
| Crealinc Ltd | Professional & scientific | 2025 |
| Creatif Technologiez Limited | Information & communication | 2012 |
| Creative Conservatory Blinds LLP | | 2019 |
| Creative Construction (Essex) Limited | Construction | 2026 |
| Creative Design LAB Ltd | Information & communication | 2019 |
| Creative Radio Partnership Limited | Information & communication | 2010 |
| Creativeninjas Ltd | Professional & scientific | 2026 |
| Crestlea Limited | Construction | 2024 |
| Creteuk Limited | Transport & logistics | 2012 |
| Crewdene Limited | Other services | 1988 |
| Crewify Limited | Information & communication | 2025 |
| Crmaesthetics Ltd | Other services | 2026 |
| Crocker & Hawkes Ltd | Construction | 2024 |
| Croft Plumbing & Heating Ltd | Construction | 2013 |
| Crowland Meadows Development Limited | Construction | 2024 |
| Crown Healthcare (London) Ltd | Health & social care | 2022 |
| Crown Jewellery Ltd | Wholesale & retail | 2023 |
| CROWN007 Ltd | Wholesale & retail | 2023 |
| Crownex Logistics Ltd | Transport & logistics | 2024 |
| Crownfleet (Logistics) Limited | Administrative & support | 2019 |
| Crownstone College Limited | Education | 2026 |
| Croydon Managment Company Limited | Hospitality | 2025 |
| Crozzled Productions Limited | Arts & recreation | 2022 |
| CRS Complete Refurbishment Services Ltd | Construction | 2026 |
| Crystal Drives and Patios Ltd | Construction | 2018 |
| Crystitopy Ltd | Construction | 2023 |
| CSA Used Car Sales Ltd | Wholesale & retail | 2012 |
| Csell Holdings Ltd | Financial services | 2025 |
| Csfg Consulting Ltd | Professional & scientific | 2025 |
| Csfw Ltd | Other services | 2023 |
| CSL Home Furnishings and Stores Ltd | Wholesale & retail | 2026 |
| CTH Electrical Services Ltd | Energy | 2019 |
| CTS Electrical Contractors Ltd | Construction | 2019 |
| Cube in Design and Build Ltd | Construction | 2023 |
| Cube in Estate Ltd | Real estate | 2024 |
| Cube Properties Group Ltd | Real estate | 2023 |
| Cubicle 5 Ltd | Real estate | 2021 |
| Cubicspace Limited | Administrative & support | 1997 |
| Cuckolds' Island Limited | Real estate | 1970 |
| Cullen Mill Property Limited | Construction | 2016 |
| Cult Classic Tattoo Limited | Arts & recreation | 2011 |
| Culture Beat Ltd | Administrative & support | 2013 |
| Cummins & Jennings Ltd | Administrative & support | 2011 |
| Cupita Limited | Real estate | 2024 |
| Curran Property Limited | Real estate | 2024 |
| Currency Times LLP | | 2023 |
| Curry Club Hornchurch Limited | Hospitality | 2022 |
| Curry Passage Limited | Hospitality | 2010 |
| Custom Booth Ltd | Manufacturing | 2025 |
| Custom Build Bros Ltd | Manufacturing | 2021 |
| Custom Plumbing & Heating Limited | Construction | 2017 |
| Customair Limited | Energy | 2026 |
| Custombuilders Limited | Construction | 2020 |
| Customs & Distribution Services Ltd | Transport & logistics | 2018 |
| Cute Corner Ltd | Wholesale & retail | 2021 |
| CV & Sons Properties Ltd | Real estate | 2019 |
| CWR Capital Ltd | Administrative & support | 2015 |
| Cyberthinc Limited | Information & communication | 1996 |
| Cycle Cellar Ltd | Wholesale & retail | 2013 |
| Cynthia Nerih Enterprises Ltd | Information & communication | 2022 |
| CYP Therapy Ltd | Health & social care | 2023 |
| D & B Technical Systems Limited | Construction | 2003 |
| D & D Fleet Engineering Limited | Professional & scientific | 2017 |
| D & E Construct Limited | Construction | 2014 |
| D Bird Property Investments Limited | Real estate | 2025 |
| D G B Moreton Electrical Ltd | Construction | 2014 |
| D Georgiev Ltd | Other services | 2010 |
| D K Contracts Ltd | Real estate | 2016 |
| D M Bond Limited | Hospitality | 2013 |
| D Muirden Plumbing & Heating Ltd | Construction | 2017 |
| D S Electrical Services UK Limited | Construction | 2006 |
| D&D Construction Group Ltd | Construction | 2024 |
| D&E Civils Ltd | Construction | 2025 |
| D&H Software Solutions Ltd | Information & communication | 2017 |
| D&K Harris Investments Limited | Financial services | 2026 |
| D&O Interiors Finishing Ltd | Construction | 2021 |
| D&R Empire Solutions Ltd | Professional & scientific | 2024 |
| D-Tech Fire Systems Limited | Administrative & support | 2007 |
| D.A Property Rentals Ltd | Real estate | 2019 |
| D.C. Cleaners Limited | Administrative & support | 2003 |
| D.Dobrev Ltd | Other services | 2015 |
| D.E.Decor(Uk) Ltd | Construction | 2003 |
| D.Jarvis Heating and Plumbing Limited | Construction | 2012 |
| D.Raj & Company Limited | Real estate | 1961 |
| D2D Organics UK Ltd | Hospitality | 2022 |
| D2D Removal Services Ltd | Transport & logistics | 2023 |
| D9 Hosting Limited | Information & communication | 2009 |