| Britalicious Ltd | Hospitality | 2017 |
| British Gaskets Limited | Manufacturing | 1947 |
| British Seals & Rubber Mouldings Limited | Wholesale & retail | 1969 |
| Brocblok Ltd | Wholesale & retail | 2025 |
| Brodie House Management Limited | Households | 1971 |
| Brookfield Place Limited | Administrative & support | 2014 |
| Broomfield Cottages Limited | Real estate | 2012 |
| Brow Envy (Essex) Limited | Other services | 2017 |
| Brundon Estates Limited | Construction | 2015 |
| Bryan Gardiner Joinery Services Limited | Construction | 2011 |
| Bryants Building Services Limited | Construction | 2010 |
| BSJ Property Developments Limited | Real estate | 2004 |
| BT Fitness Online Coaching Ltd | Arts & recreation | 2023 |
| Buckingham Management (Edgware) Limited | Extraterritorial | 1995 |
| Buddie's Waste Limited | Water & waste | 2026 |
| Build to Rent Homes Limited | Information & communication | 2017 |
| Buildus Ltd | Manufacturing | 2013 |
| Bulmer Brick and Tile Foundation | Other services | 2025 |
| Bumblebees Sensory and Messy Play Limited | Health & social care | 2026 |
| Bunny Boundaries Limited | Administrative & support | 2025 |
| Burdall Holdings Limited | Financial services | 2026 |
| Bures Business Consultants Limited | Professional & scientific | 2003 |
| Burger Amour Asset Holdings Limited | Other services | 2021 |
| Burkitts Lane Garage Limited | Wholesale & retail | 2021 |
| Burnerserve Limited | Construction | 2005 |
| Burwell Drive Managements Limited | Households | 1986 |
| Bury Installations Ltd | Construction | 2023 |
| Bury ST Edmunds Friendly Orchestra Limited | Arts & recreation | 2017 |
| Business Helping Business Ltd | Other services | 2026 |
| Business Reply Direct Mail Limited | Professional & scientific | 2010 |
| Business Reply UK Limited | Administrative & support | 2003 |
| Busy Bees Cosmetics Limited | Manufacturing | 2018 |
| Butcher Contracting Limited | Construction | 2017 |
| BY Choice (Hadleigh) Limited | Real estate | 2012 |
| BY Choice Estate Agents Limited | Extraterritorial | 2007 |
| Byron & the Bard Limited | Wholesale & retail | 2023 |
| Byte Agency Ltd | Professional & scientific | 2024 |
| C Allan Consultancy Ltd | Professional & scientific | 2016 |
| C and C Contractors Ltd | Construction | 2019 |
| C and S Electrical Ltd | Construction | 2019 |
| C G Civil & Groundwork Contractors Limited | Construction | 2014 |
| C Howard Contracting Limited | Agriculture & fishing | 2014 |
| C W Haulage Ltd | Transport & logistics | 2015 |
| C Waldock Ltd | Construction | 2004 |
| C-Mros Ltd | Professional & scientific | 2007 |
| C.H. Wallace (Sales & Marketing) Limited | | 1986 |
| Cabello Suffolk Ltd | Other services | 2023 |
| Cable & Engineering Limited | Professional & scientific | 2002 |
| Cable & Loom Ltd | Wholesale & retail | 2023 |
| Cable TIE and Parts Ltd | Wholesale & retail | 2025 |
| Cal-Ty Stoves Ltd | Energy | 2019 |
| Caley House Management Company Limited | Households | 2019 |
| Cambridge Medimould Limited | Manufacturing | 2026 |
| Cambridge Stoke College Limited | Public administration | 2018 |
| Cameo Court (Berryfields) Management Company Limited | Households | 2019 |
| Cameron Close and Justin Place Residents Management Company Limited | Households | 2006 |
| Camomfs Limited | Health & social care | 2016 |
| Camps Road Management Company Limited | Real estate | 2003 |
| Canbalance Limited | Health & social care | 2020 |
| Canter Construction Ltd | Manufacturing | 2024 |
| Car Wash 4 U Ltd | Administrative & support | 2020 |
| Car Washer UK Ltd | Information & communication | 2016 |
| Carewrx Systems Ltd | Information & communication | 2015 |
| Carnegie Consultancy Limited | Construction | 1986 |
| Carshalton Beeches Management Company Limited | Households | 2012 |
| Carters Cafe (Essex) Limited | Hospitality | 2023 |
| Casabella House of Beauty Limited | Other services | 2014 |
| Castle Roofing Limited | Construction | 2017 |
| Castleacre Designs Limited | Construction | 2007 |
| Castlings Festival Ltd | Arts & recreation | 2025 |
| Catch the FOX Ltd | Professional & scientific | 2015 |
| Causefx Digital Solutions Limited | Hospitality | 2022 |
| Cavendish Court Slough Limited | Professional & scientific | 1998 |
| Cavendish Fencing Ltd | Construction | 2019 |
| Cavendish Maltings Management Limited | Households | 1991 |
| Celia Bobak Limited | Information & communication | 2009 |
| Cello Energy Limited | Construction | 2018 |
| Centralfast Property Management Limited | Households | 1995 |
| CG Warner Limited | Construction | 2012 |
| Champ Productions Limited | Information & communication | 2023 |
| Champion Champignon Ltd | Agriculture & fishing | 2023 |
| Champions of Change Football Ltd | Arts & recreation | 2025 |
| Chapel Lane Furniture Limited | Manufacturing | 2026 |
| Chapman & SON (Haverhill) Limited | Extraterritorial | 2006 |
| Charles Cooper Specialist Decorators Ltd | Construction | 2018 |
| Charles Ping Limited | Professional & scientific | 2021 |
| Charmope Limited | Financial services | 1970 |
| Charnwood Court Management Company Limited | Households | 1993 |
| Chequers Park Limited | Hospitality | 2018 |
| Cherry Tree Sudbury Limited | Hospitality | 2023 |
| Chester and King Roofing Ltd | Construction | 2024 |
| Chestnut Court (Silvanglen) Residents Association Limited | Households | 1990 |
| Chicken Shed Creations Ltd | Manufacturing | 2015 |
| Chilton Grain Limited | Wholesale & retail | 1972 |
| Chilton Joinery Limited | Construction | 1984 |
| Chislehurst Caves Limited | Wholesale & retail | 2023 |
| Christopher Bullock Limited | Administrative & support | 2014 |
| Christopher Court Limited | Professional & scientific | 2006 |
| Christopher Lodge Residents Limited | Households | 2004 |
| Chrystal (Farms) Limited | Agriculture & fishing | 1948 |