| Clarking Interiors Ltd | Manufacturing | 2024 |
| Clarking Properties Ltd | Real estate | 2024 |
| Clarks Development Limited | Real estate | 2020 |
| Clarks Property Limited | Real estate | 2018 |
| Clarks Rail Training Ltd | Education | 2021 |
| Clarks Technology Solutions Limited | Manufacturing | 2022 |
| Clarks Transport Ltd | Transport & logistics | 2025 |
| Clarks Vehicle Conversions Limited | Manufacturing | 1999 |
| Clarks Vehicle Holdings Limited | Financial services | 2022 |
| Clasp (Scunthorpe) Limited | Wholesale & retail | 1984 |
| Classic Roofing Yorks Ltd | Construction | 2025 |
| Classic Seller Ltd | Wholesale & retail | 2025 |
| Classy Cars Ltd | Wholesale & retail | 2019 |
| Classy Entertainment Ltd | Extraterritorial | 2015 |
| Claston Orchards Limited | Agriculture & fishing | 2016 |
| Claud Trans Ltd | Transport & logistics | 2015 |
| Claudiu Daniel Ltd | Transport & logistics | 2025 |
| Clay Lane Storage Ltd | Administrative & support | 2025 |
| Claylane Brickwork Limited | Construction | 2022 |
| Claylane Construction Ltd | Construction | 2007 |
| Claylane Earthworks Limited | Construction | 2025 |
| Claylane Holdings Limited | Financial services | 2022 |
| Clayworth Shooting Supplies Limited | Wholesale & retail | 2018 |
| CLC Irish Limited | Hospitality | 2020 |
| Clck Ltd | Professional & scientific | 2025 |
| CLD Haulage Ltd | Transport & logistics | 2024 |
| Clean 'N' Bright Cleaning Service Limited | Administrative & support | 2018 |
| Clean City Air Limited | Construction | 2021 |
| Clean Energy Living Limited | Wholesale & retail | 2019 |
| Clean Image (West Yorkshire) Ltd | Other services | 2017 |
| Clean Power Hydrogen Group Limited | Manufacturing | 2016 |
| Clean Power Hydrogen PLC | Financial services | 2021 |
| Clean Safer Ltd | Administrative & support | 2021 |
| Clean Sneaks Ltd | Administrative & support | 2024 |
| Cleanbyanita Ltd | Transport & logistics | 2024 |
| Cleaners U Like Ltd | Administrative & support | 2015 |
| Cleaning Services D&D Ltd | Construction | 2024 |
| Cleanscapesolutions Ltd | Administrative & support | 2026 |
| Clear Finance and Insurance Ltd | Financial services | 2016 |
| Clear Patch Ltd | Wholesale & retail | 2024 |
| Clearance XL Limited | Wholesale & retail | 2016 |
| Clearhaven Group Ltd | Extraterritorial | 2026 |
| Clearpath Technologies Ltd | Extraterritorial | 2026 |
| Clearstone Property Holdings Ltd | Extraterritorial | 2026 |
| Clearstone Ventures Ltd | Extraterritorial | 2026 |
| Clearway Products Ltd | Extraterritorial | 2025 |
| Cleary Healthcare Limited | Health & social care | 2023 |
| Cleeve Materials Handling Limited | Professional & scientific | 2009 |
| Clegg&Son Scaffolding Limited | Construction | 2020 |
| Clematis Ltd | Health & social care | 2015 |
| Clemence Rogers Home Care Ltd | Health & social care | 2018 |
| Cleo & CA Limited | Transport & logistics | 2024 |
| Cleo Pizza Limited | Hospitality | 2025 |
| Cleo's Solutions Ltd | Professional & scientific | 2024 |
| Cleopatra Trade Doncaster Ltd | Wholesale & retail | 2020 |
| Cleverconversations Ltd | Education | 2011 |
| CLH PUB Partners Limited | Hospitality | 2020 |
| CLI Rigging Services Ltd | Information & communication | 2019 |
| Click Internet Sales Limited | Wholesale & retail | 2011 |
| Click N Feed Ltd | Information & communication | 2021 |
| Click Photobooth Ltd | Professional & scientific | 2023 |
| Clickdoors Kitchens and Bedrooms Ltd | Construction | 2021 |
| Clickgo Cabs Ltd | Transport & logistics | 2025 |
| Clickview Limited | Education | 2006 |
| Clifford Geotechnical Services Ltd | Professional & scientific | 2021 |
| Clifton Park Investments Limited | Construction | 2014 |
| Climatecool Energy Services Ltd | Manufacturing | 2010 |
| Clinic Plan UK Ltd | Construction | 2025 |
| Clinical Psychology North East Limited | Health & social care | 2017 |
| Cliniclear Ltd | Other services | 2025 |
| CLINTON14 Limited | Arts & recreation | 2015 |
| Clive Watson Limited | Real estate | 2024 |
| CLN Testing Ltd | Professional & scientific | 2022 |
| Close Books & Accounts Limited | Administrative & support | 2026 |
| Close Properties Limited | Real estate | 2021 |
| Close-Call Limited | Agriculture & fishing | 2017 |
| Closet Recycled Limited | Wholesale & retail | 2025 |
| Cloud 18 Golf Ltd | Wholesale & retail | 2025 |
| Cloud Colleague Ltd | Extraterritorial | 2016 |
| Cloud Gold Holding Limited | Financial services | 2018 |
| Cloud Nine Footcare Ltd | Extraterritorial | 2022 |
| Cloud Thistle Limited | Extraterritorial | 2026 |
| Clouded Domain and Web Services Ltd | Other services | 2009 |
| Clouded Web Hosting Ltd | Other services | 2009 |
| Cloudie Property Ltd | Households | 2025 |
| Cloudintegrate Ltd | Information & communication | 2026 |
| Cloudlateral Ltd | Extraterritorial | 2016 |
| Cloudstream Software Ltd | Extraterritorial | 2026 |
| Cloudtree Properties Limited | Real estate | 2023 |
| Clough Logistics Ltd | Transport & logistics | 2017 |
| Clover 44 Ltd | Wholesale & retail | 2024 |
| Clover Roofing Services Limited | Construction | 2002 |
| Clowes Vision Ltd | Real estate | 2023 |
| CLS Supplies Ltd | Wholesale & retail | 2020 |
| CLT Communications Limited | Administrative & support | 2016 |
| Club Doncaster Community Sports & Education Foundation | Arts & recreation | 2007 |
| Club Doncaster Limited | Arts & recreation | 2013 |
| Club SUB (2020) Ltd | Hospitality | 2025 |
| Club Thorne CIC | Arts & recreation | 2020 |
| Clubhouse Meadowhall Limited | Arts & recreation | 2026 |