| Briko Investment Limited | Real estate | 2026 |
| Brilliant Clean Ltd | Administrative & support | 2022 |
| Brim Burgers Ltd | Hospitality | 2019 |
| Brim Holdings Limited | Hospitality | 2021 |
| Brimlaw Films Ltd | Information & communication | 2021 |
| Brinkburn (Dunston Riverside) Management Company NO 6 Ltd | Households | 2005 |
| Brinkburn House (Dunston Riverside) Management Limited | Households | 2002 |
| Brinkburn House (Dunston Riverside) Management NO 5 Limited | Households | 2003 |
| Brinkburn House (Dunston Riverside) Management NO 9 Limited | Households | 2004 |
| Brinkburn House (Dunston Riverside) Management NO. 7 Ltd | Households | 2005 |
| Bristol Property Management Limited | Professional & scientific | 1968 |
| Brit John Ltd | Transport & logistics | 2013 |
| Britannia Executive Travel Ltd | Transport & logistics | 2019 |
| Britannia Soft Drinks Limited | Manufacturing | 1896 |
| Britchcombe Farm Limited | Arts & recreation | 2021 |
| British - Ethiopian Chamber of Commerce Limited | Other services | 2022 |
| British Safety Industry Federation Limited | Professional & scientific | 1994 |
| British Sign Language Broadcasting Trust | Administrative & support | 2008 |
| British Xylonite Company Limited(The) | Professional & scientific | 1877 |
| Britmate Ltd | Information & communication | 2023 |
| Britque Wares Ltd | Wholesale & retail | 2024 |
| Britteamfix Ltd | Construction | 2023 |
| Britvic Asset Company NO.1 Limited | Manufacturing | 2011 |
| Britvic Asset Company NO.2 Limited | Manufacturing | 2011 |
| Britvic Asset Company NO.3 Limited | Manufacturing | 2011 |
| Britvic Asset Company NO.4 Limited | Manufacturing | 2011 |
| Britvic Brands LLP | | 2011 |
| Britvic Emea Limited | Manufacturing | 1986 |
| Britvic Finance Partnership LLP | | 2011 |
| Britvic Healthcare Trustee Limited | Professional & scientific | 2007 |
| Britvic International Investments Limited | Manufacturing | 1986 |
| Britvic Limited | Manufacturing | 2005 |
| Britvic Overseas Limited | Manufacturing | 2010 |
| Britvic Pensions Limited | Professional & scientific | 2002 |
| Britvic Soft Drinks Limited | Manufacturing | 1953 |
| Brize Meadow (Apartments) Management Company Limited | Households | 2021 |
| Broad Solutions Limited | Professional & scientific | 2004 |
| Broadband Training Limited | Education | 2012 |
| Broadcast KIT Limited | Information & communication | 2024 |
| Brock House Nursery School Limited | Education | 1996 |
| Brockley Combe Management Company Limited | Households | 1982 |
| Brokins Ltd | Hospitality | 2017 |
| Bromley Park Management Company Limited | Households | 2004 |
| Bron Court Management Company Limited | Households | 1967 |
| Brono Marina 20 Ltd | Hospitality | 2025 |
| Bronte FH Limited | Hospitality | 2026 |
| Bronze Star Rose Ltd | Real estate | 2022 |
| Brook Arches Limited | Wholesale & retail | 2019 |
| Brooke Campos Limited | Wholesale & retail | 2019 |
| Brookfield Developments Ltd | Construction | 2011 |
| Brookland Recruitment Ltd | Administrative & support | 2023 |
| Brooks-Smith Media Limited | Information & communication | 2013 |
| Brookvale (Dawlish) Management Company Limited | Households | 2024 |
| Brookvale Apartments (Dawlish) Management Company Limited | Households | 2024 |
| Brookvale Management Company Limited | Households | 2019 |
| Brown Bear Property Ltd | Real estate | 2019 |
| Bruce Newton Limited | Information & communication | 2022 |
| Brue Place Residents Management Company Limited | Households | 2023 |
| Bruneval Gardens (Wellesley) Management Company Limited | Households | 2019 |
| Brunouth Services Ltd | Other services | 2021 |
| Brunswick Green Management Company Limited | Households | 2018 |
| BRW Property Ltd | Real estate | 2021 |
| Bryants Nurseries Holdings Limited | Financial services | 2014 |
| Bryants Nurseries Limited | Agriculture & fishing | 1959 |
| Bryants Property Holdings Limited | Construction | 2019 |
| Bryn Adda Phase 3 Management Company Limited | Real estate | 2012 |
| BS Data Ltd | Professional & scientific | 2012 |
| BSD EDU Ltd | Education | 2022 |
| Bsif Enterprise Limited | Administrative & support | 1995 |
| Bsml Controls Limited | Professional & scientific | 2020 |
| Bsml Facilities Management Ltd | Administrative & support | 2019 |
| Bsml Fire Protection Limited | Construction | 2022 |
| BTE Ventures Ltd | Professional & scientific | 2025 |
| Bthg Ltd | Construction | 2021 |
| BTL Construction Ltd | Construction | 2018 |
| BTS Roadside Recovery Ltd | Transport & logistics | 2025 |
| Bubbles Media Ltd | Information & communication | 2026 |
| BUBU30 Ltd | Transport & logistics | 2018 |
| Bucklers Park Estate Management Company Limited | Real estate | 2018 |
| Bucks and Herts Landscaping Group Limited | Administrative & support | 2018 |
| Bucks Boiler Installs Ltd | Construction | 2017 |
| Buckson Ltd | Extraterritorial | 2019 |
| BUD Coffee Ltd | Wholesale & retail | 2025 |
| Bude Holiday Resort Limited | Hospitality | 2013 |
| Budescu Limited | Transport & logistics | 2025 |
| Build & More Ltd | Construction | 2018 |
| Build and Own Ltd | Professional & scientific | 2019 |
| Build Supply Direct Limited | Wholesale & retail | 2025 |
| Build&Restoration Ltd | Construction | 2025 |
| Building Better Homes Ltd | Construction | 2020 |
| Building for Thrive Limited | Construction | 2016 |
| Building Hope Ltd | Other services | 2026 |
| Buildings Park Ltd | Construction | 2025 |
| Buildme Construction Ltd | Construction | 2020 |
| Buildnet UK Limited | Professional & scientific | 2012 |
| Buildsave Limited | Wholesale & retail | 1997 |
| Buildtrust Limited | Construction | 2008 |
| Bula Home Building Ltd | Transport & logistics | 2025 |
| Bulbourne Mews Ltd | Households | 2018 |
| Bull Homes Ltd | Construction | 2013 |