| Cornea Drylining Ltd | Construction | 2016 |
| Corner Brew Ltd | Hospitality | 2020 |
| Corner Case Technologies Ltd | Information & communication | 2016 |
| Corner Management Ltd | Real estate | 2020 |
| Corners Clean Ltd | Administrative & support | 2021 |
| Cornerstone Commercial Group Ltd | Financial services | 2025 |
| Cornerstone Contractors UK. Ltd. | Administrative & support | 2023 |
| Cornerstone Creates Ltd | Information & communication | 2015 |
| Cornerstone Design & Build Ltd | Construction | 2019 |
| Cornerstone Essentials Limited | Wholesale & retail | 2025 |
| Cornerstone Family Investments Limited | Real estate | 2021 |
| Cornerstone Paving Ltd | Administrative & support | 2013 |
| Cornerways Management (Wembley) Limited | Households | 1970 |
| Cornhall Consultants Ltd | Administrative & support | 2011 |
| Cornucopia Consulting Limited | Professional & scientific | 2021 |
| Cornwall Brands Limited | Professional & scientific | 2017 |
| Cornwall Court Freehold Limited | Real estate | 2022 |
| Cornwall Court RTM Company Limited | Households | 2016 |
| Corpcommerce Limited | Wholesale & retail | 2021 |
| Corporate and Specialist Move Management Limited | Administrative & support | 2012 |
| Corporate Executive Gifts Limited | Manufacturing | 2000 |
| Corporate Finance (London) Ltd | Financial services | 2001 |
| Corporate Healthcare Ltd | Health & social care | 2007 |
| Corporate Hospitality 4 ME Ltd | Wholesale & retail | 2011 |
| Corporate IT Management Ltd | Information & communication | 2010 |
| Corporate LED Limited | Professional & scientific | 2014 |
| Corporate Lets UK Limited | Hospitality | 2015 |
| Corporate Solutions Consulting Limited | Professional & scientific | 1995 |
| Corporate Talk Limited | Professional & scientific | 2006 |
| Corrado Construction Limited | Construction | 2005 |
| Correspondent Marine Limited | Extraterritorial | 1982 |
| Corrosion Consultants Limited | Professional & scientific | 2026 |
| Corrundum Construction Limited | Construction | 2000 |
| Corrundum Contractors Limited | Construction | 2017 |
| Corrundum Investments Limited | Real estate | 2016 |
| Corstec Consulting Limited | Information & communication | 2024 |
| Coruna Limited | Professional & scientific | 2009 |
| Corvex Network Ltd | Construction | 2026 |
| Cosfarma Ltd | Wholesale & retail | 2014 |
| Cosgrave Management Ltd | Construction | 2014 |
| Cosmar Facilities Ltd | Administrative & support | 2024 |
| Cosmedique Clinic Ltd | Health & social care | 2023 |
| Cosmetic Surgery (UK) Limited | Health & social care | 2005 |
| Cosmetic Tattooing Kent Ltd | Other services | 2023 |
| Cosmetics Surgery Limited | Health & social care | 2020 |
| Cosmic Attractions Ltd | Real estate | 2019 |
| Cosmic Code Consulting Limited | Information & communication | 2025 |
| Cosmic Crops Limited | Wholesale & retail | 2023 |
| Cosmic Roar Limited | Information & communication | 2022 |
| Cosmic Sines Limited | Financial services | 2023 |
| Cosmin Gicuta Construction Ltd | Construction | 2026 |
| Cosmo Property Services Limited | Real estate | 2016 |
| Cosmoses Ltd | Professional & scientific | 2014 |
| Costa Build Limited | Construction | 2014 |
| Costa Decoration Ltd | Construction | 2017 |
| Costa IT Consultancy Limited | Information & communication | 2014 |
| Costa Painting Ltd | Construction | 2024 |
| Costa Utilities Ltd | Construction | 2024 |
| Costcars Limited | Wholesale & retail | 2016 |
| Costcutter (Harrow) Limited | Wholesale & retail | 2011 |
| Costen Creative Limited | Professional & scientific | 2011 |
| Costuma Ltd | Wholesale & retail | 2011 |
| Costy Building Ltd | Construction | 2024 |
| Cosyhome Consulting Ltd | Real estate | 2022 |
| Coterm Limited | Construction | 2023 |
| Cotleigh Limited | Wholesale & retail | 2020 |
| Cotswold Cricket & Sports Ltd | Wholesale & retail | 2024 |
| Cottage Gardens and Feverfew Cottage Freehold Ltd | Real estate | 2023 |
| Cottage Laundry Limited | Other services | 2007 |
| Cotton Web UK Limited | Administrative & support | 2011 |
| Coulourloungebh Ltd | Other services | 2025 |
| Coulson Security Solutions Ltd | Administrative & support | 2026 |
| Coulterwell Property Limited | Real estate | 2022 |
| Counsel Rock Limited | Hospitality | 2002 |
| Count on Consulting Ltd | Professional & scientific | 2017 |
| Counterminers Productions Ltd | Arts & recreation | 2026 |
| Countertalk Ltd | Hospitality | 2019 |
| Counting Carbon Limited | Professional & scientific | 2023 |
| Country Advisory Services LLP | | 2011 |
| Country Homes (Ruislip) Limited | | 2000 |
| Countrywide Credit Corporation Limited | Financial services | 1989 |
| County Solutions Limited | Construction | 2023 |
| Coup Electrical Ltd | Construction | 2025 |
| Courageous Growth Co Ltd | Other services | 2018 |
| Courier & Removals Services NWL Ltd | Transport & logistics | 2026 |
| Courier Masters Ltd | Transport & logistics | 2023 |
| COURIER1 Logistics Ltd | Construction | 2020 |
| Courland Grove Residents Management Ltd | Households | 2015 |
| Course Junkie Ltd | Information & communication | 2025 |
| Courtleigh Investments Limited | Real estate | 2007 |
| Courtney Smith Solicitors LLP | | 2018 |
| Courtney's Ltd | Wholesale & retail | 2025 |
| Coutts & Goldsmith Limited | Real estate | 2022 |
| Covalent Talent Limited | Other services | 2024 |
| Covenant Film Limited | Information & communication | 2018 |
| Coventry Care Limited | Health & social care | 2018 |
| Cover Them (London) Ltd | Other services | 2010 |
| Coveted Collectibles Ltd | Wholesale & retail | 2024 |
| Cowbridge Freehold Limited | Households | 2020 |
| COX Costello & Horne (London) Limited | Professional & scientific | 2014 |