| Connellys Fencing Limited | Lancashire | 2002 |
| Conner Building Services Ltd | Harrow | 2024 |
| Connetech Limited | Ludlow | 2019 |
| Connetopia Food Ltd | Chelmsford | 2024 |
| Connevans Limited | Merstham | 1961 |
| Connexent Ltd | Bradford | 2021 |
| Connexion Developments Limited | Bristol | 1998 |
| Connexions Plastics Ltd | Barwell | 1999 |
| Connexite Ltd | London | 2023 |
| Connext Ltd | Bolton | 2011 |
| Conni's Cakes, Cookies and Coffee Ltd | Melton Mowbray | 2024 |
| Connice Ltd | London | 2023 |
| Connie's Carrot Cakes Ltd | Coulsdon | 2021 |
| Connies Cakes Ltd | Telford | 2026 |
| Connoisseur Apparel Limited | Dundee | 2006 |
| Connoisseur Collection Limited(The) | London | 1986 |
| Connoisseurs Coffee Club Ltd | Dundee | 2020 |
| Connolly Brothers (Curriers) Ltd | Tunbridge Wells | 2012 |
| Connolly Consultancy Limited | Maghera | 2022 |
| Connolly Leather Limited | Cranbrook | 2021 |
| Connolly Positech Ltd | Ballymoney | 2025 |
| Connor Coffield Wind Ltd | Hull | 2024 |
| Connor Cooper Carbon Limited | Dereham | 2024 |
| Connor Hills Welding Services Ltd | St. Leonards-On-Sea | 2019 |
| Connor Reilly Ltd | Wallsend | 2019 |
| Connor Signs Limited | Erdington | 2006 |
| Connor Solutions Limited | Tyne & Wear | 1999 |
| Connor's Building & Restoration Ltd | Liverpool | 2000 |
| Connors Bakery Limited | Hinckley | 2016 |
| Connorthompson Limited | Waltham Abbey | 2019 |
| Connswater Graphics Limited | Belfast | 1985 |
| Conocophillips (U.K.) Teesside Operator Limited | London | 2019 |
| Conolly Engineering Ltd | Blyth | 2018 |
| Conor O'Sullivan Designs Limited | Solihull | 2023 |
| Conquer Engineering Limited | Dungannon | 2020 |
| Conquer Tables Ltd | Southampton | 2023 |
| Conquered by Faith Ltd | London | 2020 |
| Conquering Horizons Limited | Exeter | 2015 |
| Conquerlakedistrict Ltd. | Keswick | 2018 |
| Conquerneering Ltd | Cardiff | 2018 |
| Conqueror Industries Limited | Hertford | 1991 |
| Conqueror Mind Ltd | London | 2025 |
| Conqueror of Gold Ltd | London | 2026 |
| Conquest Cycle Wear Ltd | Ayr | 2009 |
| Conquest Entertainment Limited | Northampton | 2019 |
| Conquest Joinery and Sectional Building Company Limited | Bolton | 1979 |
| Conquest Litho Limited | Maidstone | 1980 |
| Conquest Sports & Leisure Limited | Ayr | 2017 |
| Conquest Sportswear Limited | Ayr | 2017 |
| Conquest Vaults Limited | Southsea | 2023 |
| Conquip Engineering Group Limited | Alton | 2003 |
| Conrad Darare Ltd | Hayes | 2022 |
| Conrad Electrical and Electronic Services Ltd | Sandown | 2019 |
| Conrad Foods Ltd | Hemel Hempstead | 2017 |
| Conrad Shawcross Studio Limited | London | 2014 |
| Conrad's Carpentry Ltd | Godstone | 2021 |
| Conradie Associates Limited | Fareham | 2025 |
| Conran Homes Ltd | Cheshire | 2000 |
| Conroy's Conversions Limited | Goole | 2019 |
| Cons Carpentry Ltd | Pen-Y-Bont Ar Ogwr | 2026 |
| Consam Manufacturing Ltd | Melton Mowbray | 2020 |
| Consarc Engineering Limited | Holytown | 1937 |
| Conscience Group Ltd | London | 2017 |
| Conscience-Cobalt Limited | Watford | 2017 |
| Conscious Bites Ltd. | London | 2023 |
| Conscious Botanicals Ltd | Coventry | 2014 |
| Conscious Catering Limited | Maidenhead | 2019 |
| Conscious Concepts Ltd | Sutton | 2019 |
| Conscious Creatures Ltd | Southam | 2025 |
| Conscious Curtains Ltd | Hatfield | 2023 |
| Conscious Drinks Limited | Watford | 2018 |
| Conscious Equilibrium Ltd | London | 2022 |
| Conscious Threads Ltd | Chalfont St. Giles | 1990 |
| Conscious Walk Ltd | London | 2020 |
| Conscious Water Limited | London | 2024 |
| Conscious With Coffee Ltd | Welwyn Garden City | 2021 |
| Conscious With Coffee Roasters Ltd | Welwyn Garden City | 2021 |
| CONSCIOUSCOOKING93 Limited | London | 2026 |
| Consec Tech Management Ltd | Hove | 2019 |
| Conseg Limited | London | 2023 |
| Consensus Foods Limited | London | 2025 |
| Consensus Guillotine Engineering Limited | Ipswich | 2002 |
| Conserv Bioscience Limited | London | 2020 |
| Conservatec Ltd | Leeds | 1998 |
| Conservation & Restoration Limited | Stanford-Le-Hope | 2012 |
| Conservation by Design Limited | Bedford | 1992 |
| Conservation Chemicals Consultants Limited | Worcester | 1987 |
| Conservation Secondary Glazing Limited | Edinburgh | 2020 |
| Conservatories & Windows Centre Limited | Burton-On-Trent | 2018 |
| Conservatory Blinds Design & Manufacturing Ltd | Merton | 2002 |
| Conservatory Blinds Direct Ltd | Stockton-On-Tees | 2015 |
| Conservatory Blinds Express Ltd | Chatham | 2012 |
| Conservatory Design Specialists Limited | Blackburn | 1998 |
| Conservatory Restorations Ltd | Bridgwater | 2026 |
| Conservatory Roof Solutions Limited | Prescot | 2003 |
| Conservatory Roof Supplies Limited | Leeds | 2004 |
| Conservatory Roofing Solutions Ltd | Gloucester | 2009 |
| Conservatory Solutions Limited | Dewsbury | 2000 |
| Conservatoryland Limited | Mansfield | 1999 |
| Conserve Energy Ltd | Dereham | 2011 |