| Connect Foods UK Ltd | Wholesale & retail | 2025 |
| Connect Global Enterprises Ltd | Wholesale & retail | 2022 |
| Connect Global Foods Ltd | Wholesale & retail | 2025 |
| Connected Homes Community Ltd | Real estate | 2022 |
| Connective Pharma Limited | Wholesale & retail | 2016 |
| Connsult Ltd | Information & communication | 2015 |
| Conran Developments Limited | Construction | 2018 |
| Consolve Limited | Transport & logistics | 2015 |
| Consort Acquisitions Limited | Professional & scientific | 2011 |
| Consortium Commercial Developments Limited | Real estate | 1967 |
| Consultare Ltd | Real estate | 2023 |
| Continuplan Limited | Professional & scientific | 2023 |
| Control Energy Costs Holdings Limited | Professional & scientific | 2013 |
| Control Energy Costs Limited | Professional & scientific | 1981 |
| Cooksocket Ltd | Information & communication | 2026 |
| Coombe Properties Limited | Real estate | 1982 |
| Cooper UK Logistics Ltd | Transport & logistics | 2017 |
| Coordination Management and Documentation Company Ltd | Professional & scientific | 2011 |
| Coordination MEP Services Limited | Real estate | 2018 |
| Copyhold Works Limited | Financial services | 2021 |
| Corbin Information Consulting Ltd | Information & communication | 2020 |
| Coretones Ltd | Education | 2025 |
| Corinium Land Limited | Administrative & support | 2014 |
| Corners 65 UK Limited | Wholesale & retail | 2018 |
| Cosford Limited | Construction | 2009 |
| Cosgrove Construction Limited | Construction | 2018 |
| Cosourced Limited | Administrative & support | 2017 |
| Cosy Moose Limited | Wholesale & retail | 2020 |
| Cotelands Freehold 1-99 Limited | Households | 1997 |
| Cottesmore Management Consulting Limited | Construction | 2002 |
| Country EYE Limited | Administrative & support | 2014 |
| Courier and Passenger Transport Holdings Limited | Financial services | 2007 |
| Court & SON Limited | Agriculture & fishing | 2017 |
| Courtesy Cars Redhill Limited | Transport & logistics | 2010 |
| Covair Structures Limited | Construction | 2001 |
| Covariance Ltd | Manufacturing | 2014 |
| Coventry Street Productions Limited | Other services | 1961 |
| Coving Shop Limited | Construction | 2015 |
| Cowley | | 2001 |
| CPS Management Services Ltd | Manufacturing | 1997 |
| CPS Marine Limited | Transport & logistics | 2025 |
| Craftstones Europe Limited | Wholesale & retail | 1991 |
| Craig LEA (Hartlepool Property) Ltd | Financial services | 2025 |
| Craig LEA (Hartlepool) Ltd | Financial services | 2020 |
| Craig LEA Sangster Ltd | Financial services | 2020 |
| Craig-Star (Hartlepool) Ltd | Financial services | 2020 |
| Crawley Removals & Storage Ltd | Transport & logistics | 2020 |
| CRB Group Roofing Building Ltd | Construction | 2024 |
| Creaseys Drive (Birchwood) Management Company Limited | Households | 1982 |
| Creative Construction Co. ( Surrey ) Ltd | Construction | 2007 |
| Creative KEN Limited | Arts & recreation | 2017 |
| Creators and Curious Ltd | Wholesale & retail | 2020 |
| Cressy Associates Ltd. | Professional & scientific | 1998 |
| Cressyaccounts.Com Limited | Professional & scientific | 2008 |
| Cro-Bar Props Limited | Administrative & support | 2021 |
| Crocodile Encounters Ltd | Arts & recreation | 2011 |
| Croftcope Limited | Administrative & support | 1990 |
| Croftcope Properties Limited | Administrative & support | 2010 |
| Cromwell 2026 Ltd | Construction | 2025 |
| Crossroads Residential (Southern) Ltd | Real estate | 2023 |
| Crossroads Residential Ltd | Real estate | 2018 |
| Crosswood Consulting Ltd | Professional & scientific | 2024 |
| Crotty & Campbell Limited | Wholesale & retail | 1975 |
| Crow Gate Entertainment Ltd | Information & communication | 2017 |
| Crown Plumbing Services Limited | Construction | 2021 |
| Crucial Software Limited | Information & communication | 1998 |
| Cruze Contractors Ltd | Construction | 2022 |
| Crystal Clear Valuations Ltd. | Professional & scientific | 2017 |
| Crystal Commercial Companies Limited | Administrative & support | 2011 |
| Crystal Takeaway Limited | Hospitality | 2019 |
| CS Vehicle Sales Limited | Wholesale & retail | 2014 |
| CSS Caring Hands Ltd | Construction | 2016 |
| CT Consulting Ltd. | Education | 2004 |
| CT Insurance Systems Limited | Financial services | 1971 |
| CT London Consultancy Limited | Professional & scientific | 2020 |
| Ctest Ltd | Information & communication | 2018 |
| Ctrl Break Consulting Ltd | Information & communication | 2017 |
| Ctrl Commerce Limited | Information & communication | 2022 |
| CTS Dental Holdings Limited | Professional & scientific | 2004 |
| CTS Dental Retail Supplies Limited | Real estate | 2009 |
| CTS Dental Supplies Limited | Professional & scientific | 1993 |
| CU Associates Limited | Professional & scientific | 2005 |
| Cubair Engineering Services Ltd. | Manufacturing | 2003 |
| Cubair Flight Training Limited | Arts & recreation | 1996 |
| Cubic Defence UK Ltd. | Wholesale & retail | 2001 |
| Cubic Sales Limited | Professional & scientific | 2009 |
| Cubikind Ltd | Wholesale & retail | 2026 |
| Cunningham & Cunningham Limited | Professional & scientific | 2012 |
| Cura Beauty UK Limited | Wholesale & retail | 2010 |
| Curio Architects Limited | Professional & scientific | 2022 |
| Curious Concepts Ltd | Wholesale & retail | 2017 |
| Curtis Hutchinson Communications Limited | Professional & scientific | 2017 |
| Custom Canal Craft Limited | Manufacturing | 2013 |
| Custom Divers Limited | Manufacturing | 1994 |
| Cyber Advertising Ltd | Information & communication | 2012 |
| Cyber Security Intelligence Limited | Information & communication | 2013 |
| Cygentic Ltd | Information & communication | 2025 |
| Cygnets Childcare Nurseries Limited | Education | 2014 |
| Cygnets Holiday Cottages Ltd | Hospitality | 2022 |
| D & C Jaron Pederson Ltd | Wholesale & retail | 2021 |