| Choccablok Ltd | Professional & scientific | 2013 |
| Choice Shenfield Ltd | Hospitality | 2019 |
| Chopsy's Cafe Ltd | Hospitality | 2018 |
| Chorus Business Advisers Ltd | Administrative & support | 2014 |
| Chris Bull Limited | Real estate | 2012 |
| Christine Wyatt Consulting Limited | Professional & scientific | 2019 |
| Christmas Farm Limited | Agriculture & fishing | 2013 |
| Christmas Tree Delivery Limited | Construction | 2014 |
| Christmas Tree Growers Limited | Agriculture & fishing | 2013 |
| Chromecarbon Ltd | Information & communication | 2020 |
| Chromefast UK Limited | Manufacturing | 2021 |
| CHS Accident Repair Group Ltd | Wholesale & retail | 2024 |
| CHS Central Ltd | Administrative & support | 2024 |
| Chucker.Io Ltd | Information & communication | 2023 |
| Chucs Restaurants Limited | Hospitality | 2020 |
| Church House Farm Livery Limited | Agriculture & fishing | 2008 |
| Church Mews Management Company (Hockley) Limited | Professional & scientific | 2018 |
| Cine 54 Limited | Professional & scientific | 2022 |
| Cinquecento (Greek Street) Limited | Hospitality | 2021 |
| Cissbury Associates Ltd | Administrative & support | 2019 |
| City & Essex (London) Ltd | Administrative & support | 2008 |
| City A/C Limited | Construction | 2016 |
| City Apartments Leigh-On-Sea RTM Company Limited | Households | 2025 |
| City ARC Group Ltd | Administrative & support | 2019 |
| City Cladding Solutions Ltd | Construction | 2022 |
| City Land London Ltd | Real estate | 2026 |
| City Land Properties (Europe) Limited | Real estate | 2014 |
| Cityplan Building Facilities Ltd | Manufacturing | 2001 |
| CJ Professionals Limited | Professional & scientific | 2024 |
| CJ Social Housing Limited | Administrative & support | 2021 |
| Cj's Butchers Limited | Manufacturing | 2024 |
| CJH Financial Consulting Ltd | Financial services | 2020 |
| Cjnh Services Ltd | Administrative & support | 2021 |
| CJW Wealth Ltd | Financial services | 2023 |
| CK High Rise Window Solutions Ltd | Administrative & support | 2022 |
| CL Propco Limited | Real estate | 2026 |
| CL Trade Co Limited | Professional & scientific | 2026 |
| Clacton Regent Football Club Limited | Arts & recreation | 2025 |
| Clacton Vaping Limited | Wholesale & retail | 2016 |
| Cladding UP Ltd | Construction | 2022 |
| Clancy Enterprise Ltd | Information & communication | 2019 |
| Clarence House Property Management Limited | Households | 2006 |
| Clarity CC Ltd | Construction | 2022 |
| Clarity Cura Ltd | Health & social care | 2023 |
| Clarity Engineering Ltd | Professional & scientific | 2020 |
| Clarity Finance Partners Ltd | Professional & scientific | 2022 |
| Clark Property Estates Ltd | Real estate | 2024 |
| Clarke & King Ltd | Real estate | 2020 |
| Clarke and Wheate Holdings Limited | Financial services | 2020 |
| Clarke Pharmacy Limited | Wholesale & retail | 2022 |
| Clarkes Contracts (Southern) Ltd | Construction | 2021 |
| Clarkes Contracts Ltd | Construction | 2018 |
| Clarkes Developments Ltd | Real estate | 2024 |
| Clarkes Hire Company Ltd | Administrative & support | 2019 |
| Clarkes Holdings Limited | Financial services | 2019 |
| Clarkes Management Limited | Professional & scientific | 2019 |
| Claro Pall Mall Ltd. | Financial services | 2016 |
| Classic Motor Yachts Limited | Manufacturing | 2021 |
| Claudiacreative Limited | Wholesale & retail | 2011 |
| Clayland Sinclair Limited | Information & communication | 2013 |
| Claylens Mills Ltd | Administrative & support | 2011 |
| Clean Coders Ltd | Information & communication | 2015 |
| Clean Energy Certificates Ltd | Financial services | 2025 |
| Clean Green Cleaning Services Limited | Administrative & support | 1992 |
| Clean Green Cleaning Solutions Limited | Administrative & support | 2017 |
| Clean Green Property Maintenance Services Limited | Administrative & support | 2009 |
| Clean Therm Ltd | Construction | 2025 |
| Cleaner ME Ltd | Administrative & support | 2021 |
| Cleanestt Ltd | Administrative & support | 2023 |
| Clear and Clean (Clacton) Ltd | Water & waste | 2025 |
| Clear Choice Stairlifts Ltd | Professional & scientific | 2018 |
| Clear Path Home Harrow Ltd | Health & social care | 2023 |
| Clear Telecom and Data Limited | Information & communication | 2003 |
| Clear Telecom Limited | Extraterritorial | 2007 |
| Clearaway Holdings Limited | Financial services | 2015 |
| Clearaway Recycling Limited | Transport & logistics | 2010 |
| Clearpaths Healthcare Ltd | Public administration | 2024 |
| Cleen Windows Limited | Professional & scientific | 2024 |
| Clements Building and Construction Ltd | Construction | 2023 |
| Clevercoms Limited | Professional & scientific | 2000 |
| CLG Consultancy Ltd | Professional & scientific | 2024 |
| Cliclift UK Ltd | Extraterritorial | 2022 |
| Cliff Crabb Kitchen Installations Ltd | Construction | 2020 |
| Cliff Heights Investments Limited | Real estate | 2017 |
| Clifford & Mitchell Antiques Limited | Wholesale & retail | 2025 |
| Clifford Electrics Limited | Construction | 2012 |
| Clifton Mews Limited | Real estate | 2023 |
| Climate and Nature Advisory Ltd | Professional & scientific | 2025 |
| Climatec Home Improvements Ltd | Construction | 2009 |
| Climatec Group Holdings Limited | Financial services | 2020 |
| Climatec Windows Limited | Manufacturing | 1993 |
| Climatetech Engineering Ltd | Information & communication | 2023 |
| Clinica Ltd | Other services | 2025 |
| Clip Clop (Ashford) Limited | Wholesale & retail | 2013 |
| Close Reach Investments Limited | Real estate | 2019 |
| Cloud Anorak Limited | Information & communication | 2021 |
| Cloud Technology Office Ltd | Professional & scientific | 2021 |
| Clouders (Audit & Accounts) Limited | Professional & scientific | 1999 |
| CLP Properties (London) Limited | Real estate | 2024 |
| Club Consultancy Services Limited | Administrative & support | 2018 |