| Criss SF Ltd | Transport & logistics | 2024 |
| Crissdan Trans Ltd | Transport & logistics | 2024 |
| Cristian Bulgaru Ltd | Transport & logistics | 2019 |
| Cristian Cleaning Ltd | Administrative & support | 2025 |
| Critical Care London (CCL) Limited | Health & social care | 2010 |
| CRM Developments Limited | Construction | 2019 |
| CRM Insights Ltd | Administrative & support | 2016 |
| CRM Property Holdings Limited | Real estate | 2019 |
| CRM Vent Ltd | Construction | 2025 |
| CRO Group Ltd | Financial services | 2024 |
| CRO78 Limited | Health & social care | 2022 |
| Crocodile Engineering Ltd | Professional & scientific | 2017 |
| Crofts Edge Ltd | Real estate | 2023 |
| Cromwell Finance Ltd | Professional & scientific | 2018 |
| Crooton Ltd | Professional & scientific | 2019 |
| Cross Country Housing CIC | Hospitality | 2024 |
| Cross Country Logistics Ltd | Transport & logistics | 2015 |
| Cross County Scaffolding Limited | Construction | 2025 |
| Cross Wires Ltd | Construction | 2025 |
| Crossacre Holdings Limited | Professional & scientific | 2011 |
| Crossacre Properties Limited | Real estate | 2011 |
| Crossfire Protection Ltd | Administrative & support | 2014 |
| Crossfit Strength Station Limited | Arts & recreation | 2019 |
| Crossing Transport Ltd. | Transport & logistics | 2015 |
| Crossways Recoveries Ltd | Wholesale & retail | 2019 |
| Crowdsafe Solutions UK Ltd | Administrative & support | 2019 |
| Crowland Abbey Hotel Limited | Real estate | 2015 |
| Crowland Barber Shop Ltd | Other services | 2026 |
| Crowland Barbers Ltd | Other services | 2024 |
| Crowland Car Wash Ltd | Wholesale & retail | 2021 |
| Crowland Care Ltd | Health & social care | 2025 |
| Crowland Carpets Ltd | Wholesale & retail | 2014 |
| Crowland Cars Ltd | Transport & logistics | 2026 |
| Crowland Cranes (Holdings) Limited | Financial services | 2018 |
| Crowland Cranes Limited | Construction | 1995 |
| Crowland Fresh Produce Limited | Wholesale & retail | 2004 |
| Crowland Stays Ltd | Hospitality | 2021 |
| Crown & Ledger Ltd | Professional & scientific | 2025 |
| Crown Barclay Limited | Construction | 2013 |
| Crown Home Developments Ltd | Construction | 2016 |
| Crown Integrated Energy Ltd | Construction | 2018 |
| Crown Kindergartens Limited | Education | 2001 |
| Crown Resource Solutions Ltd | Health & social care | 2010 |
| Crown Transport Solutions Ltd | Transport & logistics | 2025 |
| Crown Tyres & Services Ltd | Wholesale & retail | 2025 |
| Crown Windows & Repairs UK Limited | Construction | 2015 |
| Crown Windows Property Maintenance Ltd | Construction | 2024 |
| Crownify Commerce Limited | Wholesale & retail | 2026 |
| CRS (Eastern) Limited | Water & waste | 2009 |
| Crucial Look Ltd | Wholesale & retail | 2025 |
| CRUISE4U Ltd | Administrative & support | 2022 |
| Crunchy Snacks Limited | Wholesale & retail | 2017 |
| Cruzology Limited | Health & social care | 2024 |
| Crypto Munch Ltd | Information & communication | 2025 |
| Crystal Accountancy & Tax Solutions Ltd | Professional & scientific | 2004 |
| Crystal Automotive Group Ltd | Wholesale & retail | 2024 |
| Crystal Community Properties Ltd | Real estate | 2023 |
| Crystal Events and Design Ltd | Hospitality | 2020 |
| Crystal Peacock Jewels Ltd | Wholesale & retail | 2024 |
| Crystalair Limited | Energy | 1991 |
| Crystalline Properties Limited | Real estate | 2023 |
| Crystone Ltd | Other services | 2017 |
| CS Carpentry (Peterborough) Ltd | Construction | 2016 |
| CS Sallows Limited | Wholesale & retail | 2024 |
| CS Supplies (Installations) Ltd | Professional & scientific | 2021 |
| CSA Accountants UK Limited | Extraterritorial | 2017 |
| CSC Plumbing Heating Ltd | Construction | 2024 |
| CSE Cleaning Services Limited | Administrative & support | 2026 |
| CSL Property Ltd | Real estate | 2023 |
| Csma Transport Ltd | Transport & logistics | 2024 |
| CT Hauliers Ltd | Transport & logistics | 2022 |
| CT Heaven Catering Ltd | Hospitality | 2020 |
| CT Imed Ltd | Health & social care | 2018 |
| CT Peterborough Limited | Administrative & support | 2017 |
| CT Physio Services Limited | Health & social care | 2018 |
| CT Project Services Ltd | Professional & scientific | 2025 |
| CT25DXR Ltd | Transport & logistics | 2024 |
| Ctax Management Limited | Professional & scientific | 2002 |
| CTE Services (Electrical) Ltd | Construction | 2026 |
| CTE Services (Holdings) Ltd | Financial services | 2024 |
| CTE Services (Investments) Ltd | Real estate | 2025 |
| CTE Services (Plumbing and Heating) Ltd | Construction | 2026 |
| CTE Services Ltd | Construction | 2015 |
| CTK Services Limited | Health & social care | 2007 |
| CTS Bathrooms Ltd | Construction | 2020 |
| CTX Hub Ltd | Wholesale & retail | 2023 |
| Cuan Ltd | Professional & scientific | 2023 |
| Cube Designz Ltd | Information & communication | 2021 |
| CUE Club Limited | Hospitality | 2022 |
| Cuesta Woolf BTL Ltd | Real estate | 2025 |
| Cuesta Woolf Ltd | Real estate | 2024 |
| Culpeck Insurance Services Ltd. | Financial services | 1987 |
| Cultural Connect CIC | Education | 2023 |
| Culture Connect Exchange CIC | Professional & scientific | 2026 |
| Cultureosity Limited | Information & communication | 2026 |
| Culturesight Global Ltd | Professional & scientific | 2024 |
| Cummins Generator Technologies Limited | Manufacturing | 1947 |
| Cupertino Code Ltd | Professional & scientific | 2025 |
| Cupolish Ltd | Construction | 2003 |
| Cura Medica Company Ltd | Administrative & support | 2016 |