| Chiggs Limited | Education | 2015 |
| Chii Homes Ltd | Real estate | 2024 |
| Chilli Chop Co Limited | Manufacturing | 2018 |
| China Centre Point Ltd | Professional & scientific | 2011 |
| Chirol Ventures Ltd | Construction | 2020 |
| Choice Living Developments Ltd | Real estate | 2020 |
| Chopal Ltd | Hospitality | 2023 |
| Chottas Limited | Other services | 2023 |
| Chris & EMS Ltd | Transport & logistics | 2022 |
| Chrisdjanee Beauty Parlour Ltd | Other services | 2020 |
| Chrisdjanee Incorporated Services Limited | Administrative & support | 2015 |
| Chrispuni Ltd | Health & social care | 2022 |
| Christols Plus Limited | Administrative & support | 2017 |
| Christy Building Ltd | Construction | 2019 |
| Chrypka Ltd | Transport & logistics | 2019 |
| Ci&Opex Services Limited | Manufacturing | 2024 |
| CIE Ltd | Construction | 1959 |
| CIE UK (Holdings) Ltd | Financial services | 1988 |
| CIL Cleaning Services Ltd | Administrative & support | 2021 |
| Circus of Anthems Ltd | Arts & recreation | 2025 |
| Cirelle Associates Limited | Financial services | 2002 |
| CIT Ltd | Construction | 2024 |
| Citadel Learning Ltd | Education | 2024 |
| City Connect Transfers Limited | Transport & logistics | 2026 |
| City Construction Services Limited | Construction | 2015 |
| City Electrical & Property Services Limited | Construction | 2020 |
| City Washroom Services Ltd | Administrative & support | 2012 |
| Cityhall Associates Ltd | Construction | 2004 |
| Civic City | Education | 2024 |
| Civicedge Consulting Ltd | Professional & scientific | 2025 |
| Cj's @ Europa Ltd | Extraterritorial | 2011 |
| Cj's Transport & Logistics Ltd | Transport & logistics | 2025 |
| CJC Performance Ltd | Arts & recreation | 2020 |
| CJL Heritage Developments Limited | Construction | 2025 |
| CJW Distribution Ltd | Wholesale & retail | 2022 |
| CKB Homes Ltd | Real estate | 2019 |
| Cladcore Solutions Ltd | Construction | 2025 |
| Cladcraft Ltd | Professional & scientific | 2025 |
| Cladpromi Ltd | Construction | 2024 |
| Claire Horton PR Ltd | Administrative & support | 2017 |
| Clampin Building Contractors Ltd | Construction | 2019 |
| Clare Home Care Ltd | Public administration | 2025 |
| Clarendon Home Improvements Essex Ltd | Construction | 2022 |
| Clarendon Solar Essex Limited | Energy | 2024 |
| Clas Transport Ltd | Transport & logistics | 2022 |
| Clauautos Limited | Transport & logistics | 2018 |
| Clavin Property Development Ltd | Households | 2025 |
| Clean and Sparkling Ltd | Manufacturing | 2026 |
| Clean Home (UK) Ltd | Administrative & support | 2014 |
| Clean IT 4 YOU Ltd | Administrative & support | 2021 |
| Clean Sweep Ltd | Administrative & support | 2004 |
| Clear Motors Ltd | Wholesale & retail | 2020 |
| Cleargate Corporation Ltd | Administrative & support | 1999 |
| Clearskyroofingandsolar Ltd | Construction | 2025 |
| Clearways School of Motoring Limited | Education | 2001 |
| Clearwins Consulting Ltd | Professional & scientific | 2025 |
| Cleland Designs Ltd | Professional & scientific | 2016 |
| Clerk of Works Ltd | Construction | 2007 |
| Clever Accountants Ltd | Professional & scientific | 2014 |
| Click & Read Limited | Wholesale & retail | 2025 |
| Click 24/7 Limited | Professional & scientific | 2021 |
| Click and Collect IT Ltd | Wholesale & retail | 2024 |
| Click Assist Ltd | Other services | 2016 |
| Click N Create Media Limited | Professional & scientific | 2010 |
| Clickable Collection Ltd | Wholesale & retail | 2023 |
| Clickbenefit Ltd | Information & communication | 2013 |
| Clifford Devlin Employee Ownership Trustees Limited | Administrative & support | 2020 |
| Clifford Devlin Fire Protection Limited | Construction | 2023 |
| Clifford Devlin Limited | Construction | 1962 |
| CLM Accountants Ltd | Professional & scientific | 2024 |
| CLM British Solutions Ltd | Administrative & support | 2021 |
| Clothing Direct Online Limited | Wholesale & retail | 2017 |
| Cloud CAB Ltd | Transport & logistics | 2026 |
| Cloud Capsule Ltd | Wholesale & retail | 2024 |
| Cloud Ideas Limited | Information & communication | 2023 |
| Cloudarch Ltd | Information & communication | 2025 |
| Cloudcampus Ltd | Education | 2026 |
| Cloves Indian Takeaway Ltd | Hospitality | 2015 |
| Club 21 GEA Limited | Arts & recreation | 2024 |
| CM Care Providers Limited | Health & social care | 2025 |
| Cmcs HOUSE2GO Ltd | Real estate | 2024 |
| CMP Property Holdings Ltd | Real estate | 2021 |
| CMT Consultancy Ltd | Information & communication | 2024 |
| CMT Finance Limited | Financial services | 2025 |
| CMY Transport Ltd | Transport & logistics | 2023 |
| CN I.T Consulting Ltd | Professional & scientific | 2009 |
| CN Properties 3 UK Limited | Real estate | 2019 |
| CN Trans Ltd | Transport & logistics | 2026 |
| CNB Bakehouse Ltd | Manufacturing | 2025 |
| CNB Estates Ltd | Real estate | 2025 |
| CNB Logistics Ltd | Transport & logistics | 2025 |
| CNB Supplies Limited | Wholesale & retail | 2025 |
| CNB Vent Limited | Construction | 2022 |
| Cnbn Ltd | Information & communication | 2014 |
| CND Trans Logistics Ltd | Transport & logistics | 2024 |
| CNT Standart Limited | Construction | 2021 |
| Coal City Bukka London Ltd | Hospitality | 2025 |
| Coapchain Group Ltd | Other services | 2015 |
| Coast Care Group Ltd | Health & social care | 2022 |
| Coco Business Lounge Limited | Wholesale & retail | 2020 |