| Coney Hill Farm Creamery Ltd | York | 2024 |
| Confection by Design Limited | Harrogate | 1998 |
| Confectionaryonline Limited | London | 2025 |
| Confectionery Kingdom Ltd | London | 2025 |
| Confederate Chemicals GRP Limited | Newtown | 2014 |
| Conference of Socialist Economists | Newcastle Upon Tyne | 2004 |
| Confetti Constellations Limited | Nottingham | 2005 |
| Confex Technology (Holdings) Limited | Poole | 2014 |
| Confex Technology Limited | Poole | 1993 |
| Confi-Dent (UK) Ltd | Burntwood | 2007 |
| Confidence Plus Ltd | East Kilbride | 2019 |
| Confidential Records (UK) Limited | Snaith | 2009 |
| Confido Racing Limited | Moulsford | 2008 |
| Configarray Ltd | Poole | 2015 |
| CONFIGURATIONS4WORK Ltd | Northenden | 2025 |
| Configure 8 Limited | Hampshire | 2002 |
| Confirm Bakery Ltd | Hull | 2024 |
| Confitex UK Limited | Slough | 2017 |
| Confloor Ltd | Bristol | 2025 |
| Conformance Quality Consultants Ltd | Prescot | 2020 |
| Conformis UK Limited | London | 2013 |
| Conformity Assessment Services Ltd | London | 2021 |
| Conga Fitness Ltd | Essex | 2021 |
| Conga Limited | Ipswich | 2015 |
| Congatec Embedded UK Limited | London | 2016 |
| Congaton Ltd | Cardiff | 2024 |
| Conglomerate Spirits Ltd. | Glasgow | 2017 |
| Congo Engineering Ltd | Dungannon | 2023 |
| Conica Ltd | Newark | 1990 |
| Conicality Ltd | Dingwall | 2023 |
| Conidia Bioscience Limited | Guildford | 2000 |
| Conifer Joinery Ltd | Kidlington | 2005 |
| Conilon Ltd | London | 2013 |
| Coniston Corporate Embroidery UK Ltd | Prestwich | 1989 |
| Coniston Fibres Limited | Keighley | 1999 |
| Coniston Stonecraft 2020 Ltd | Cheltenham | 2020 |
| Conjugation Ltd | Belper | 2021 |
| Conjunct Limited | Edinburgh | 2004 |
| Conjure Candles Limited | London | 2022 |
| Conka Elite Limited | London | 2021 |
| Conkea.Com Ltd | Belfast | 2026 |
| Conker Bespoke Frames Limited | Norwich | 2022 |
| Conker Bespoke Furniture Limited | Nottingham | 2017 |
| Conker Furniture Limited | Norwich | 2024 |
| Conker Living Limited | Nantwich | 2017 |
| Conker Shoes Limited | Totnes | 2013 |
| Conker Spirit Limited | Bournemouth | 2014 |
| Conker Tree Ltd | Southampton | 2021 |
| Conkers Wood and Metal Crafts Ltd | Abingdon | 2021 |
| Conks Ltd | Barry | 2025 |
| Conlan Electrical Services Ltd | Plymouth | 2022 |
| Conlog UK Limited | London | 2023 |
| Conlon Plant Services Limited | Musselburgh | 2015 |
| Conlon Repair Solutions Limited | Sheffield | 2025 |
| Connabride (UK) Limited | London | 2017 |
| Connate Naturals Ltd | London | 2025 |
| Connaught Conservatory Roofs Ltd | Rotherham | 2006 |
| Connaught Motor Co (2014) Ltd | Swaffham | 2013 |
| Connaught Motorcycles Ltd | Swaffham | 2020 |
| Connect & Play Ltd | London | 2025 |
| Connect Brand Ltd | Preston | 2017 |
| Connect Business Technology Limited | Ringwood | 1996 |
| Connect Ecosystems Limited | Kelty | 2004 |
| Connect EMS Limited | Maidstone | 2021 |
| Connect Engineering Limited | Manchester | 1995 |
| Connect Everything Aerospace Limited | Banbury | 2020 |
| Connect Exhibitions Limited | Canterbury | 2000 |
| Connect Hygiene Products Ltd | Telford | 2013 |
| Connect Infrared Limited | Halesowen | 2024 |
| Connect Kitchens Limited | Manchester, United Kingdom | 2023 |
| Connect Medical Systems Limited | Oldham | 2007 |
| Connect Mobile Limited | London | 2025 |
| Connect Plumbing & Heating Limited | | 2005 |
| Connect Services DJC Ltd | Croydon | 2021 |
| Connect Studio Ltd | Horsham | 2026 |
| CONNECT2MARKETS Ltd | Burnley | 2008 |
| Connected AV Ltd | Dunfermline | 2014 |
| Connected by Silk Limited | Staines-Upon-Thames | 2021 |
| Connected Destinations Limited | London | 2018 |
| Connected Electrical Solutions UK Limited | London | 2016 |
| Connected Energy Ltd | Newcastle Upon Tyne | 2010 |
| Connected Fanatics Ltd | London | 2021 |
| Connected Kerb Limited | London | 2017 |
| Connected Management Services Limited | Bath | 2025 |
| Connected Response Limited | Edinburgh | 2019 |
| Connected System Solution UK Ltd | London | 2018 |
| Connected to Homes Ltd | Peterborough | 2018 |
| Connected to the Streets Ltd | London | 2026 |
| Connectedwith Ltd | Hereford | 2024 |
| Connection Works Education Consultancy Ltd | Belper | 2016 |
| Connectiq Ltd | Stonehouse | 2003 |
| Connectix Limited | Braintree | 1993 |
| Connector Solutions Limited | High Wycombe | 2006 |
| Connector Subsea Power Systems Ltd | Leeds | 2026 |
| Connector Subsea Solutions (UK) Ltd | Wednesbury | 2017 |
| Connectors & Switchgear Limited | Banbury | 1970 |
| Connectrend Limited | Greater London | 2022 |
| Connectric Ltd | London | 2024 |
| Connelly Furniture Ltd | Wallsend | 2023 |
| Connelly Sports Ltd | Coarbridge | 2019 |