| Caradon Anodising Company Limited | Manchester | 1946 |
| Caradon Lenses Limited | Manchester | 1982 |
| Caralto Holdings Ltd | Bolton | 2023 |
| Caralto Wholesale Ltd | Bolton | 2023 |
| Carav Limited | London | 2023 |
| Caravan Accessories Limited | Kenilworth | 2017 |
| Caravan and Motorhome Club Limited | East Grinstead | 2000 |
| Caravan Financial Services Limited | Newtownards | 1985 |
| Caravan Sales Centre Limited | Atherstone | 2007 |
| Caravan Site Finder Ltd | Cheltenham | 2021 |
| Caravan Supplies Limited | Poynton | 2016 |
| Caravan World Limited | Colchester | 2022 |
| Caravankingdom Ltd | Bracknell | 2025 |
| Caravans in the Sun Limited | Burton-On-Trent | 2007 |
| Carawal Limited | Northampton | 2023 |
| Carb Steel for General Contracting and Public Supplies Ltd | London | 2026 |
| Carbeth Limited | Edinburgh | 2010 |
| Carbis Tiling Company Ltd | Y Barri | 2024 |
| Carbis Water Parking Limited | St. Ives | 2008 |
| Carbon 2018 Limited | Sandhurst | 2019 |
| Carbon Accountability Limited | | 2007 |
| Carbon Careful Limited | London | 2025 |
| Carbon Char Limited | Doncaster | 2025 |
| Carbon Delight Ltd | Wickford | 2008 |
| Carbon Free Ltd | Kings Langley | 2008 |
| Carbon Harvest SCI & Tech Co., Ltd | Kenilworth | 2019 |
| Carbon Harvesting Contracts Limited | Warrington | 2007 |
| Carbon IP Solutions Limited | London | 2014 |
| Carbon Neutral Network Ltd | Barnet | 2006 |
| Carbon NKD Ltd | Colchester | 2020 |
| Carbon Offset Credits Limited | Harrogate | 2012 |
| Carbon Reporting Marketplace Limited | London | 2023 |
| Carbon Research Limited | Newcastle Upon Tyne | 1982 |
| Carbon Sink Ltd | Andover | 2024 |
| Carbon Solution Technologies Ltd | London | 2011 |
| Carbon Underwriting Holdings Limited | London | 2022 |
| CARBON360 Limited | Brierley Hill | 2025 |
| CARBON8 Aggregates Limited | East Wretham | 2019 |
| Carbonado Investment Limited | Manchester | 2023 |
| Carbonaid Ltd | Stroud | 2004 |
| Carboncable Ltd | Burgess Hill | 2024 |
| Carboncraftuk Ltd | Liverpool | 2024 |
| Carboniferous Limited | Nottingham | 2013 |
| Carbonlite Solar Limited | Littleborough | 1997 |
| Carbonoptix Limited | Disley | 2014 |
| Carboot Guru Ltd | Bordon | 2024 |
| Carbootfairs Ltd | Worcester | 2000 |
| Carbrey Group Ltd | Cheltenham | 2014 |
| Carbrooke Hall Estate Building Company Limited | Thetford | 2014 |
| Carbulbs Ltd | Wakefield | 2014 |
| Carcharodon Capital Ltd | London | 2020 |
| Carclo Group Services Limited | Mitcham | 1911 |
| Carclo Investments Limited | Mitcham | 1925 |
| Carclo Securities Limited | Mitcham | 1943 |
| Carclo Technical Plastics (Mitcham) Limited | Mitcham | 1984 |
| Carclo Technical Plastics (Slough) Limited | Mitcham | 1936 |
| Carclo Zephyr Limited | Mitcham | 1968 |
| Carculator Limited | Hitchin | 2021 |
| Card Connection Limited | Dewsbury | 1992 |
| Card Service Provider UK Limited | Stafford | 2012 |
| Cardale Freehold Limited | Harrogate | 2018 |
| Cardamon Waves Ltd | London | 2021 |
| Cardanat Properties Limited | Macclesfield | 2014 |
| Cardano Limited | London | 2016 |
| Cardeasy Limited | Hemel Hempstead | 1999 |
| Carden & Co (Malpas) Ltd | Chester | 2016 |
| Carden Road Management Company Limited | Harrow | 2007 |
| Cardenden 69 Limited | Lochgelly | 2013 |
| Cardgains Limited | Sheffield | 2023 |
| Cardiac Insight Limited | Swansea | 2014 |
| Cardiff Airport Taxis Limited | Llantwit Major | 2005 |
| Cardiff and Vale Tutors Limited | Cardiff | 2019 |
| Cardiff Biologicals Limited | Brecon | 2006 |
| Cardiff Boating Limited | Pontypridd | 2017 |
| Cardiff Drain Cleaning Company Limited | Cardiff | 2003 |
| Cardiff Limited | Porthcawl | 2021 |
| Cardiff Part Exchange Center Ltd | Cardiff | 2019 |
| Cardiff Period Developments Limited | Swansea | 2006 |
| Cardiff Pet Health Limited | Bristol | 2008 |
| Cardiff Protides Limited | Brecon | 2005 |
| Cardiff Retail Assets (NO 2) Limited | Manchester | 2013 |
| Cardiff Retail Assets Limited | Manchester | 2013 |
| Cardiff Scaffolding Limited | Cardiff | 2010 |
| Cardiff Storage Company Ltd | Estate Llanishen | 1996 |
| Cardinal & Kohain Ltd | Surbiton | 2018 |
| Cardinal Clinic Ltd | Wokingham | 2016 |
| Cardinal Investment Properties Limited | Milton Keynes | 2012 |
| Cardinal Services UK Limited | London | 2008 |
| Cardinals Lincoln Limited | Louth | 2025 |
| Cardio Vision Services Limited | Ebbw Vale | 2024 |
| Cardioat Limited | Lutterworth | 2021 |
| Cardiopath Limited | Edinburgh | 1999 |
| Cardizoo UK Ltd | London | 2021 |
| Cardon Holdings Limited | Wymondham | 2004 |
| Cardooo Limited | Manchester | 2014 |
| Cardoso Hnos Ltd | London | 2023 |
| Cardrew Court Limited | London | 2005 |
| Cardrome (UK) Limited | Taunton | 1998 |
| Cardrome Vehicle Solutions Limited | Hornchurch | 2005 |
| Cards, the Universe and Everything Ltd | Heathfield | 2023 |