| Conferience Ltd | Information & communication | 2014 |
| Confidence BUS & Coach Hire Ltd | Transport & logistics | 2026 |
| Confidence BUS & Coach Ltd. | Transport & logistics | 2003 |
| Confident Communities | Education | 2014 |
| Conflictedheartsch Limited | Wholesale & retail | 2025 |
| Conform Engineering Ltd | Construction | 2024 |
| Conglutina Memoria Ltd | Wholesale & retail | 2026 |
| Conifer Lodge Holdings Ltd | Professional & scientific | 2007 |
| Conifer Lodge Limited | Health & social care | 1998 |
| Coniston Amble Ltd | Wholesale & retail | 2025 |
| Conker Editions Ltd | Information & communication | 2017 |
| Connaught Place Great Glen Management Ltd | Construction | 2020 |
| Connect Facilities and Services Limited | Administrative & support | 2022 |
| Connect & Convert Media Ltd | Professional & scientific | 2025 |
| Connect & Create Associates Ltd | Health & social care | 2026 |
| Connect 4 Energy Limited | Construction | 2019 |
| Connect 4 Voice and Data Ltd | Information & communication | 2016 |
| Connect Boston Properties Ltd | Real estate | 2022 |
| Connect Direct Ltd | Professional & scientific | 2023 |
| Connect Furniture Ltd | Wholesale & retail | 2026 |
| Connect Home Care Services Limited | Health & social care | 2023 |
| Connect Infra Ltd | Construction | 2016 |
| Connect Integrated Services Ltd | Information & communication | 2018 |
| Connect Sports Social Enterprise CIC | Education | 2022 |
| Connect Tech Solutions Limited | Information & communication | 2006 |
| Connect to Learn Ltd | Administrative & support | 2024 |
| Connect With Impact Ltd | Professional & scientific | 2020 |
| Connect Worlds for Recruitment Ltd | Transport & logistics | 2026 |
| Connected Accident Repair Solutions Ltd | Professional & scientific | 2016 |
| Connected Dots Ltd | Information & communication | 2021 |
| Connected Security Solutions Ltd | Administrative & support | 2021 |
| Connectin RPO Ltd | Administrative & support | 2022 |
| Connecting - Mental Health Solutions in Education CIC | Education | 2024 |
| Connectonic Limited | Information & communication | 2020 |
| Connectus Utilities Limited | Administrative & support | 2023 |
| Connester Limited | Real estate | 2024 |
| Connexify Consulting Ltd | Information & communication | 2023 |
| Connexus Restaurant Limited | Hospitality | 2017 |
| Connie's African Restaurant and PUB Ltd | Hospitality | 2025 |
| Connolly Property Services (Leics) Limited | Construction | 2024 |
| Connor Security Services Ltd | Administrative & support | 2019 |
| Connor's Car Valeting Ltd | Administrative & support | 2022 |
| Conor Harrison Ltd | Health & social care | 2023 |
| Conscia Design Ltd | Professional & scientific | 2026 |
| Consciouscave Limited | Wholesale & retail | 2021 |
| Consigliere Rahima Ltd | Professional & scientific | 2016 |
| Consilium B Ltd | Real estate | 2024 |
| Consort Commercials Limited | Financial services | 2017 |
| Consort Design & Build Limited | Construction | 2023 |
| Consortium 3 Ltd | Wholesale & retail | 2021 |
| Consortium Leicester Limited | Real estate | 2013 |
| Constant and Co Roofing Ltd | Construction | 2024 |
| Constellation (Leicester) Holdings Limited | Financial services | 2019 |
| Constellation IX Limited | Information & communication | 1995 |
| Construct Training Services Limited | Information & communication | 2019 |
| Construction 5 Ltd. | Construction | 2020 |
| Construction by Acacia Ltd | Construction | 2019 |
| Construction Chemicals (UK) Limited | Wholesale & retail | 1997 |
| Construction Chemicals Limited | Wholesale & retail | 2003 |
| Construction Equipment UK Limited | Wholesale & retail | 2017 |
| Construction Interior Design Holdings Ltd | Construction | 2024 |
| Construction LUX Ltd | Construction | 2020 |
| Construction of Buildings Company Ltd | Construction | 2026 |
| Construction One Limited | Construction | 2025 |
| Construction Plus Limited | Construction | 2019 |
| Construction ROM Ltd | Construction | 2025 |
| Consul Concepts Ltd | Professional & scientific | 2020 |
| Consult Legal Ltd | Real estate | 2025 |
| Consult Medical Services Ltd | Health & social care | 2021 |
| Consultancy and Support Services Ltd | Professional & scientific | 2026 |
| Consultancyservices 247 Ltd | Professional & scientific | 2024 |
| Consultant Property Services Limited | Administrative & support | 1990 |
| Consultus (Pemxq) Limited | Professional & scientific | 2006 |
| Consultus Assured Energy Limited | Administrative & support | 2016 |
| Consultus Energy Investments Limited | Administrative & support | 2025 |
| Consultus International UK (the Energy Brokers) Limited | Administrative & support | 1994 |
| Consultus Resilience Limited | Professional & scientific | 2018 |
| Consultus Sustainability Limited | Administrative & support | 2023 |
| Consultus Worldwide Limited | Professional & scientific | 2016 |
| Consumer Credit Trade Association | Other services | 1891 |
| Contact Cultures Properties Ltd | Real estate | 2024 |
| Container Office Limited | Construction | 2025 |
| Contech Property Services Ltd | Construction | 2021 |
| Contego Fire & Acoustic Limited | Construction | 1994 |
| Contemporary Aluminium Glazing Systems Ltd | Construction | 2015 |
| Contemporary Properties & Protection Ltd. | Real estate | 2021 |
| Content & Data Systems Limited | Information & communication | 2015 |
| Context Psychology Ltd | Education | 2025 |
| Continental Car Sales Ltd | Wholesale & retail | 2025 |
| Continued Healthcare Limited | Health & social care | 2021 |
| Contour Beauty Aesthetics Ltd | Other services | 2018 |
| Contract Vinyls Ltd | Construction | 2020 |
| Contractors Recruitment Ltd | Professional & scientific | 2022 |
| CONTRACTS4YOU Ltd | Professional & scientific | 2018 |
| Contrary Motion Ltd | Education | 2026 |
| Contrast Steel Band CIC | Education | 2023 |
| Control Centre Solutions Limited | Construction | 2012 |
| Control Panel Services Holdings Limited | Professional & scientific | 2018 |
| Control Panel Services Limited | Manufacturing | 2003 |
| Conuovo Limited | Professional & scientific | 2014 |