| Bridgewater Property Limited | Real estate | 2021 |
| Bridgeway Motors Ltd | Wholesale & retail | 2026 |
| Bridgeway Property Solutions Limited | Real estate | 2026 |
| Bridon Holdings Limited | Professional & scientific | 2010 |
| Bridon International Ltd. | Manufacturing | 1946 |
| Bridon Limited | Professional & scientific | 1924 |
| Bridon Steel Limited | Professional & scientific | 1929 |
| Bridon-Bekaert Ropes Group Ltd | Professional & scientific | 2014 |
| Brier Hills Limited | Agriculture & fishing | 2008 |
| Brier Hills Recycling Limited | Agriculture & fishing | 2004 |
| Brierfield House Care Limited | Health & social care | 2018 |
| Brigg & Bay Ltd | Hospitality | 2025 |
| Bright & Day Solicitors Ltd | Professional & scientific | 2021 |
| Bright & Sons Limited | Wholesale & retail | 1899 |
| Bright Blue Sky Financial Solutions Limited | Financial services | 2022 |
| Bright Fame Investments Ltd | Financial services | 2007 |
| Bright Future Business Ltd | Hospitality | 2018 |
| Bright Hill Holdings Limited | Other services | 2025 |
| Bright Horison Services Limited | Wholesale & retail | 2024 |
| Bright Side Services UK Ltd | Administrative & support | 2024 |
| Bright Vision Engineering Consultancy Ltd | Extraterritorial | 2015 |
| Brightbridge Design Ltd | Information & communication | 2025 |
| Brightcart Retail Ltd | Extraterritorial | 2026 |
| Brightcore Electrical Ltd | Construction | 2019 |
| Brightcore Solutions Ltd | Wholesale & retail | 2018 |
| Brightech Solutions Ltd | Construction | 2024 |
| Brighter Build (Holdings) Limited | Construction | 2022 |
| Brighter Build Limited | Construction | 2018 |
| Brighter Days Wellbeing Community Interest Company | Health & social care | 2021 |
| Brighter Futures Learning Partnership Trust | Education | 2012 |
| Brighter Minds Counselling & Psychotherapy Ltd | Health & social care | 2025 |
| Brighter Properties Limited | Real estate | 2006 |
| Brighter Prospects Ltd | Education | 2024 |
| Brightforge Media Ltd | Financial services | 2026 |
| Brightfox Ventures Ltd | Extraterritorial | 2026 |
| Brightmoor Collective Ltd | Extraterritorial | 2026 |
| Brightmoor Innovations Ltd | Extraterritorial | 2025 |
| Brighto Painting & Maintenance Limited | Construction | 2023 |
| Brightpath Wealth Ltd | Financial services | 2023 |
| Brightspire Learning Group Ltd | Extraterritorial | 2025 |
| Brillica Ltd | Administrative & support | 2025 |
| Brillica Properties Ltd | Real estate | 2025 |
| Brindle Vehicle Solutions Ltd | Wholesale & retail | 2026 |
| Brindlecore Group Ltd | Extraterritorial | 2026 |
| Brindleforge Ltd | Extraterritorial | 2026 |
| Brinkhurst Electrical Engineering Ltd | Construction | 2026 |
| Brinova Group Ltd | Information & communication | 2026 |
| Bristol Event Catering Company Limited | Hospitality | 2020 |
| Britampco Limited | Manufacturing | 2022 |
| Britcoin Chainlink Ltd | Extraterritorial | 2025 |
| Britcool Ltd | Manufacturing | 2025 |
| British Association of Sport and Exercise Medicine | Education | 1985 |
| British Gurkhas Nepalese Community Doncaster Ltd | Real estate | 2025 |
| British Ropes Limited | Professional & scientific | 1962 |
| Brits Pitz Limited | Financial services | 2021 |
| Brittain Farming Limited | Agriculture & fishing | 2009 |
| Britz Health Care Ltd | Health & social care | 2021 |
| Brix Catering and Events Limited | Hospitality | 2026 |
| Brix Entertainment Doncaster Ltd | Hospitality | 2025 |
| Bro's Barber (Doncaster) Limited | Other services | 2025 |
| Broad Futures Ltd | Real estate | 2025 |
| Broadgate (Residents) Limited | Households | 1973 |
| Broadway Holiday Parks Ltd | Real estate | 2025 |
| Broadway Parks Ltd | Construction | 2023 |
| Brock & Co Properties Limited | Real estate | 2007 |
| Brockholes Ltd | Wholesale & retail | 2020 |
| Brocklesby Services Ltd | Wholesale & retail | 2019 |
| Brodericks GBC Limited | Professional & scientific | 2005 |
| Brogan at Sorelle Ltd | Other services | 2019 |
| Brogan Construction Limited | Construction | 2007 |
| Brogan Rose Holdings Limited | Real estate | 2023 |
| Broken Bangers Ltd | Wholesale & retail | 2025 |
| Brolam Scooters Limited | Wholesale & retail | 2008 |
| Brompton Climate Services Ltd | Energy | 2021 |
| Bromsgrove Legal Ltd | Professional & scientific | 2014 |
| Bronx Properties Limited | Real estate | 2023 |
| Brook Babes (Holdings) Ltd | Real estate | 2023 |
| Brook House Barn Management Limited | Other services | 2025 |
| Brooke and Family Property Investments Ltd | Real estate | 2014 |
| Brooke Farming Company Limited | Agriculture & fishing | 2007 |
| Brookfield Consultancy Ltd | Professional & scientific | 2022 |
| Brookfield Country Sports Ltd | Arts & recreation | 2023 |
| Brookfield Electrical Ltd | Construction | 2016 |
| Brookfield Renewable Energies Ltd | Construction | 2016 |
| Brookfield Solar Maintenance Ltd | Manufacturing | 2016 |
| Brookhousing Ltd | Construction | 2025 |
| Brooklands Trade Developments Limited | Real estate | 2006 |
| Brooks Podiatry Ltd. | Health & social care | 2013 |
| Brookvale Management Company (2) Limited | Real estate | 2019 |
| Brookway Financial Ltd | Financial services | 2021 |
| Broom Land and Property Services Ltd | Administrative & support | 2021 |
| Broscombe South Limited | Transport & logistics | 2017 |
| Brothers Pyrotechnics (UK) Limited | Manufacturing | 2006 |
| Brothers Recycling Limited | Transport & logistics | 2026 |
| Brovent Global Ltd | Information & communication | 2014 |
| Brow Politics Ltd | Other services | 2024 |
| Brown Family Enterprises Ltd | Other services | 2023 |
| Brown Property Partners Limited | Real estate | 2025 |
| Brown Suga Tanning & Nail Studio Limited | Other services | 2015 |
| Brown Traffic Ltd | Construction | 2022 |