| Confectionery MCR Ltd | Wholesale & retail | 2018 |
| Conferences UK Limited | Information & communication | 2004 |
| Conferma Limited | Information & communication | 2006 |
| Confessional Lutheran Church Ltd | Other services | 2025 |
| Confiance International Ltd | Wholesale & retail | 2025 |
| Confidance Academy Ltd | Education | 2025 |
| Confidence After Cancer Limited | Professional & scientific | 2024 |
| Confidence Pharmacy Ltd | Wholesale & retail | 2018 |
| Confidencemanagementconsultancy Limited | Hospitality | 2020 |
| Confident Dental Agency Ltd | Administrative & support | 2023 |
| Confident Smile Solutions Limited | Health & social care | 2026 |
| Confidental Solutions Limited | Health & social care | 2013 |
| Confido Partners Limited | Other services | 2018 |
| Confirmed Shopper Limited | Wholesale & retail | 2022 |
| Confirmzen Ltd | Information & communication | 2025 |
| Conforma Fire Ltd | Construction | 2022 |
| Conforma Holdings Ltd | Financial services | 2026 |
| Cong Thanh Ltd | Other services | 2025 |
| Cong. Yetev LEV D'Satmar M/C Ltd | Other services | 2006 |
| Congleton Car Wash Ltd | Administrative & support | 2018 |
| Congrats Ltd | Extraterritorial | 2023 |
| Congruent Constructions Limited | Construction | 2025 |
| Congruent Healthcare Services Limited | Health & social care | 2023 |
| Congruis Limited | Information & communication | 2008 |
| Conifers House Management Company Limited | Households | 2016 |
| Conister Consultants Limited | Administrative & support | 1999 |
| Coniston Investment Holdings Ltd | Financial services | 2025 |
| Coniston Mini Market Ltd | Wholesale & retail | 2022 |
| Conker PR Limited | Professional & scientific | 2007 |
| Conlead Ltd | Wholesale & retail | 2025 |
| Conlupo Ltd | Extraterritorial | 2023 |
| Conlux Ltd | Construction | 2025 |
| Connahs Quay 1 Limited | Real estate | 2025 |
| Connahs Quay Estates Ltd | Real estate | 2021 |
| Connahs Quay Limited | Real estate | 2019 |
| Connaught Asset Management Limited | Financial services | 2007 |
| Connaught Facilities Limited | Construction | 2014 |
| Connaught Fencing Limited | Construction | 2015 |
| Connaught Land & Development Ltd | Construction | 2021 |
| Connaught Logistic Support Limited | Professional & scientific | 2022 |
| Connaughton & Wildman Limited | Real estate | 2020 |
| Connaughton Consultancy Ltd | Education | 2022 |
| Connaughton Ltd. | Professional & scientific | 2015 |
| Connecor (UK) Limited | Administrative & support | 1998 |
| Connect 4 Compliance Ltd | Professional & scientific | 2018 |
| Connect Accounting & Business Ltd | Professional & scientific | 2015 |
| Connect ACS Lighting Limited | Information & communication | 2021 |
| Connect Alliance Trust | Education | 2013 |
| Connect Cctv Systems Limited | Information & communication | 1999 |
| Connect Collaborations Ltd | Professional & scientific | 2021 |
| Connect Electric (Bury) Limited | Construction | 2009 |
| Connect Electrical & Data Limited | Construction | 2020 |
| Connect Electrical North West Ltd | Construction | 2023 |
| Connect Electrix Ltd | Construction | 2024 |
| Connect Engineering Limited | Manufacturing | 1995 |
| Connect Healthcare Solutions Ltd | Information & communication | 2022 |
| Connect Homes Support Limited | Real estate | 2021 |
| Connect in Events Limited | Other services | 2009 |
| Connect in WPW Limited | Financial services | 2023 |
| Connect Maintenance Limited | Construction | 2021 |
| Connect Medex Ltd | Administrative & support | 2013 |
| Connect OP Property Management Ltd | Real estate | 2022 |
| Connect Parking Limited | Information & communication | 2024 |
| Connect Pharma Limited | Wholesale & retail | 2016 |
| Connect Relationship Consultancy Limited | Health & social care | 2022 |
| Connect Sphere Media Limited | Professional & scientific | 2025 |
| Connect Supported Living Ltd | Health & social care | 2015 |
| Connect UK Education Ltd | Health & social care | 2022 |
| Connect Worldwide Property Ltd | Real estate | 2025 |
| CONNECT2 Consulting Limited | Professional & scientific | 2019 |
| CONNECT21 Ltd | Real estate | 2019 |
| Connected Car Services Limited | Transport & logistics | 2023 |
| Connected for Television Limited | Information & communication | 2017 |
| Connected Impact Limited | Information & communication | 2022 |
| Connected Information Technology Solutions Ltd | Information & communication | 2025 |
| Connected IT Contract Limited | Information & communication | 2017 |
| Connected IT Recruitment Ltd | Administrative & support | 2015 |
| Connecteleven Limited | Information & communication | 2015 |
| Connecting Dots Events Limited | Arts & recreation | 2026 |
| Connecting Dots Group Ltd | Arts & recreation | 2022 |
| Connecting Manchester Ltd | Other services | 2025 |
| Connection 1ST Ltd | Professional & scientific | 2026 |
| Connection Point Ltd | Information & communication | 2022 |
| Connectix Communications Ltd | Information & communication | 2022 |
| Connectmcr Ltd | Professional & scientific | 2020 |
| Connectserv Ltd | Administrative & support | 2023 |
| Connectwithjapan Ltd | Administrative & support | 2018 |
| Connectzrus Ltd | Wholesale & retail | 2025 |
| Connekt Trade Limited | Wholesale & retail | 2020 |
| Connekt-Uk Ltd | Administrative & support | 2024 |
| Connell & Finnigan Limited | Wholesale & retail | 1953 |
| Connell Construction Recruitment Ltd | Administrative & support | 2021 |
| Connell Developments (NW) Limited | Professional & scientific | 2005 |
| Connell Developments Limited | Construction | 1993 |
| Connerstone Properties Limited | Real estate | 2020 |
| Connery Legal Ltd | Professional & scientific | 2015 |
| Connex One Limited | Information & communication | 2013 |
| Connex One Solutions Limited | Information & communication | 2021 |
| Connex One Technology Limited | Information & communication | 2021 |
| Connexage Business Group Ltd | Administrative & support | 2026 |