| Brignel Ltd | Real estate | 2025 |
| Brij Consulting Ltd | Administrative & support | 2010 |
| Brij Impex Ltd | Wholesale & retail | 2021 |
| Brino Ltd | Wholesale & retail | 2018 |
| Brit Academy Ltd | Education | 2019 |
| Britannic Worldwide Limited | Extraterritorial | 2007 |
| Britestone Enterprises Ltd | Information & communication | 2024 |
| British Deaf Sports Council Limited | Arts & recreation | 1991 |
| Brizlab Ltd | Information & communication | 2025 |
| Broadgate 20 Limited | Real estate | 2018 |
| Broadway 9DA Limited | Administrative & support | 2024 |
| Brobbs Co Ltd | Transport & logistics | 2025 |
| Brobuilt Ltd | Wholesale & retail | 2025 |
| Brookmans Roofing Limited | Construction | 2024 |
| Broomling Ltd | Information & communication | 2022 |
| Broomling Stays Ltd | Hospitality | 2022 |
| Broomling Technologies Ltd | Financial services | 2022 |
| BS Associates Limited | Professional & scientific | 2018 |
| BS Builders Construction Ltd | Construction | 2020 |
| BS Electrical Systems Limited | Administrative & support | 2013 |
| Bskeja Construction Ltd | Construction | 2018 |
| BT Decorating Solutions Limited | Construction | 2021 |
| BT Homes Taunton Ltd | Real estate | 2026 |
| Buachi Limited | Manufacturing | 2014 |
| Buckinghamshire Paving Solutions Limited | Construction | 2024 |
| Buckley Site Services Limited | Construction | 2015 |
| Buckleys Building Services Limited | Construction | 2014 |
| Budu Consulting Limited | Real estate | 2024 |
| Bugs Tree Care Ltd | Agriculture & fishing | 2026 |
| Build Property Limited | Real estate | 2015 |
| BUILD2TODAY Ltd | Construction | 2025 |
| Buildnova Ltd | Construction | 2015 |
| Bulidx Ltd | Construction | 2025 |
| Bullss Oceanss Ltd | Information & communication | 2022 |
| Bureaupal Limited | Administrative & support | 2022 |
| Bush PIE and Mash Limited | Hospitality | 2022 |
| Business Consultancy Management Solutions Limited | Professional & scientific | 2014 |
| Butcher Parks (FOX Court) Limited | Hospitality | 2022 |
| Butchers Lodge and Lakes Ltd | Hospitality | 2025 |
| Buyers and Sellers Ltd | Extraterritorial | 2011 |
| Buymultimart Ltd | Manufacturing | 2024 |
| Buzz & Co Ltd | Construction | 2011 |
| Buzz Electrical Services Ltd | Construction | 2007 |
| Buzz Marketing Limited | Manufacturing | 2000 |
| BY17 Limited | Hospitality | 2021 |
| BY17 WH Limited | Hospitality | 2024 |
| Byas Design Ltd | Professional & scientific | 2012 |
| Bymat Ltd | Real estate | 2025 |
| Byrne Engineering & Construction Limited | Construction | 2014 |
| Bythorne House Management Company Limited | Administrative & support | 2002 |
| C a Brickwork (Slough) Limited | Construction | 2003 |
| C J Contracts (UK) Limited | Construction | 2014 |
| C J Laing Property Maintenance Ltd | Manufacturing | 2019 |
| C J R Scenery Limited | Information & communication | 2011 |
| C K T Electrical Limited | Construction | 2014 |
| C L.Contracts Ltd | Construction | 2020 |
| C P Digital Ltd | Information & communication | 2015 |
| C S Bedford Limited | Wholesale & retail | 2003 |
| C Simpson Ltd | Professional & scientific | 2021 |
| C&C Best Maintenance Limited | Construction | 2023 |
| C&E Building Specialist Ltd | Construction | 2026 |
| C&T Electrical Contractors Ltd | Construction | 2015 |
| C.N.Nameplate Co., Limited | Wholesale & retail | 2023 |
| CAB Construction Limited | Construction | 2010 |
| CAB Data Ltd | Other services | 2019 |
| Cabana 18 Ltd | Wholesale & retail | 2020 |
| Cabaret Leaseco Limited | Real estate | 2026 |
| Cabaret Opsco Ltd | Hospitality | 2026 |
| Cabezo Ltd | Manufacturing | 2014 |
| Cadpro Services Limited | Professional & scientific | 2007 |
| Caister Properties Limited | Real estate | 1960 |
| Cake+ Limited | Manufacturing | 2021 |
| Calbrataz Ltd | Professional & scientific | 2020 |
| Calm Before the Storm Limited | Information & communication | 2009 |
| Calry Consulting Engineers Limited | Professional & scientific | 2020 |
| Cambridge HR Consultants Limited | Administrative & support | 2009 |
| Camelot Building Services Ltd | Construction | 2023 |
| Camelot Roofing & Building Solutions Limited | Construction | 2017 |
| Camelot Solutions Limited | Construction | 2023 |
| Cameron Spencer Relocations Limited | Transport & logistics | 2019 |
| CAN Drainage Limited | Construction | 2012 |
| Cangzhou Honghu Electrical Manufacturing Co., Ltd | Wholesale & retail | 2023 |
| Canine Capers Ltd | Other services | 1998 |
| Cantwell Relocations Limited | Administrative & support | 2020 |
| Capital Markets Search & Selection Limited | Administrative & support | 2007 |
| Capsure Consulting Limited | Professional & scientific | 2019 |
| Car Products Ltd | Wholesale & retail | 2013 |
| Car Specialist Group Ltd | Professional & scientific | 2025 |
| Car Valeting Limited | Other services | 2025 |
| Cara Group Ltd | Real estate | 2025 |
| Caravaan Group Ltd | Hospitality | 2025 |
| Care 4 Yours Ltd | Health & social care | 2019 |
| Care Agency Services Ltd | Health & social care | 2023 |
| Care Services Group Ltd | Health & social care | 2025 |
| Career Development College London Ltd | Education | 2020 |
| Careerforces Limited | Administrative & support | 2019 |
| Carely for Import and Export Ltd | Wholesale & retail | 2024 |
| Caribbean Glow Ltd | Other services | 2020 |
| Carlton Roofing & Property Care Limited | Construction | 2024 |
| Carlton Roofing & Windows Ltd | Construction | 2019 |