| Brightwell Investments Ltd | Real estate | 2024 |
| Brightwell Services Ltd | Other services | 2018 |
| Brightyellow Art Limited | Arts & recreation | 2016 |
| Brilliant Management Holdings Limited | Professional & scientific | 2004 |
| Brim Barnet Ltd | Hospitality | 2023 |
| Brim Watford Limited | Hospitality | 2025 |
| Bring IT on the Musical Ltd | Arts & recreation | 2015 |
| Brisea Holding LP | | 2017 |
| Bristy Ltd | Wholesale & retail | 2025 |
| Brit Asian Events (UK) Limited | Arts & recreation | 2018 |
| Britannia Cars Limited | Transport & logistics | 2021 |
| Britannia Horizons Ltd | Wholesale & retail | 2025 |
| Britannia Mode Ltd | Wholesale & retail | 2025 |
| Britanniawise Limited | Real estate | 2019 |
| Britannica Business Services Ltd | Professional & scientific | 2006 |
| Britanno Ltd | Wholesale & retail | 2025 |
| Britbridge Immigration Ltd | Other services | 2026 |
| Britdrive Motors Limited | Wholesale & retail | 2025 |
| Britfruit Logistics G.B Ltd | Construction | 2024 |
| British Association of Removers (Services) Limited | Other services | 1976 |
| British Association of Removers (Training Services) Limited | Other services | 1991 |
| British Association of Removers Limited(The) | Transport & logistics | 1914 |
| British Board of Agrément | Professional & scientific | 1966 |
| British Board of Agrément Holdings Limited | Professional & scientific | 2023 |
| British Deals Ltd | Wholesale & retail | 2024 |
| Brits Bazaar Ltd | Wholesale & retail | 2025 |
| Britween Ltd | Professional & scientific | 2025 |
| BRL Building Constructions Ltd | Construction | 2024 |
| Broad Film and Costruction Ltd | Construction | 2025 |
| Broad Logic Ltd | Other services | 2011 |
| Broadarrow Management Limited | Professional & scientific | 2016 |
| Broadfields Avenue Residents (Edgware) Limited | Real estate | 1973 |
| Broadoak Home Improvements Ltd | Construction | 2020 |
| Brocklehurst Whiston Amalgamated Limited | Professional & scientific | 1929 |
| Bromotime Limited | Information & communication | 2019 |
| Bronx International Ltd | Wholesale & retail | 1995 |
| Brook Real Estate Advisers Limited | Real estate | 2021 |
| Brook Real Estate Limited | Real estate | 2025 |
| Brook View Residents Limited | Households | 2022 |
| Brook Works Limited | Real estate | 2024 |
| Brook Workspace Limited | Real estate | 2024 |
| Brookdene Capital Advisors Limited | Professional & scientific | 2025 |
| Brookdene Holdings Ltd | Other services | 2020 |
| Brookdene Motors Ltd | Real estate | 2024 |
| Brookdene Service Centre Ltd | Wholesale & retail | 2024 |
| Brooke Yachts International Limited | Wholesale & retail | 2025 |
| Brookes Property Services Ltd | Real estate | 2025 |
| Brookplace Limited | Construction | 2001 |
| Brooks Hair Tailoring Ltd | Other services | 2025 |
| Brooks-Hill Holdings Limited | Financial services | 2018 |
| Brooks-Hill Investment Holdings Limited | Financial services | 2018 |
| Brooks-Hill Investments Limited | Professional & scientific | 2018 |
| Brooks-Hill Limited | Manufacturing | 1997 |
| Brookview Bath Limited | Construction | 2022 |
| Brotherhood Enterprise Limited | Other services | 2026 |
| Brothers Build Services Ltd | Construction | 2019 |
| Brothers-N-Law Limited | Education | 2025 |
| Brown & Brown Maintenance Services Ltd | Administrative & support | 2024 |
| Brown and Wenman Eyecare Limited | Health & social care | 2016 |
| Brown Batter Limited | Hospitality | 2025 |
| Brown Onion Consultancy Ltd. | Professional & scientific | 2025 |
| Brownie Leader Limited | Administrative & support | 2009 |
| Brownlee Properties Ltd | Real estate | 2025 |
| Brownrok Limited | Real estate | 2013 |
| Browns Integrated Technologies Ltd | Information & communication | 2000 |
| Browns Sales and Lettings Ltd | Real estate | 2021 |
| Browns Stocks and Shares Ltd | Financial services | 2025 |
| Broxbourne Dental Care Limited | Health & social care | 2009 |
| Brunch & Crunch PVT Ltd | Hospitality | 2025 |
| Brunch Banqueting Ltd | Hospitality | 2025 |
| Brunel Gate Management Company Limited | Real estate | 2013 |
| Brunswick Management Company Limited | Real estate | 1981 |
| Bryan Engineering Company (UK) Limited | | 1983 |
| BS Financial Ltd | Real estate | 2024 |
| BS Initiative Limited | Administrative & support | 2008 |
| BSA Construction Ltd | Construction | 2018 |
| BSB Trading Ltd | Information & communication | 2014 |
| BSO Production Ltd | Arts & recreation | 2017 |
| BSP Associates Ltd | Construction | 2024 |
| BSQ Holdings Ltd | Wholesale & retail | 2024 |
| BTB Builders Ltd | Construction | 2025 |
| Btech Consulting Limited | Information & communication | 2009 |
| BTN Rentals Ltd | Administrative & support | 2025 |
| Btsm Properties Limited | Real estate | 2024 |
| Bubbles Floral Studio Ltd | Wholesale & retail | 2025 |
| Bubbles&Bounce Limited | Administrative & support | 2026 |
| Buchan Advisory Limited | Professional & scientific | 2025 |
| Buckland Flats Management Limited | Extraterritorial | 1994 |
| Buckley Property Group Ltd | Real estate | 2024 |
| Bucks Tiling Company Ltd | Construction | 2026 |
| Buds and Blooms Limited | Health & social care | 2017 |
| Budur Tiling Ltd | Construction | 2025 |
| Budweiser Budvar Limited | Extraterritorial | 1980 |
| Buen Ltd | Hospitality | 2020 |
| Buglerock Ltd | Professional & scientific | 2025 |
| Buguss Ltd | Wholesale & retail | 2024 |
| Build & Beam Ltd | Construction | 2026 |
| Build a Yield Ltd | Real estate | 2018 |
| Build Better and Sale Ltd | Construction | 2024 |
| Build Trust Properties Limited | Real estate | 2025 |