| BP Source Limited | Information & communication | 2015 |
| Bpatmens Ltd | Health & social care | 2022 |
| Bpctech Limited | Information & communication | 2009 |
| BPM Builders UK Limited | Construction | 2025 |
| BPO Consulting Limited | Professional & scientific | 2012 |
| BPR Advisory Ltd | Wholesale & retail | 2025 |
| BPS Plus Limited | Administrative & support | 2006 |
| BR Capital Holdings Limited | Financial services | 2026 |
| BR Fares Ltd. | Information & communication | 2014 |
| BR Property Development One Limited | Construction | 2022 |
| Braby-Fuller Limited | Professional & scientific | 1865 |
| Brackenwood Consultancy Limited | Professional & scientific | 2013 |
| Bracknale Events Ltd. | Hospitality | 2015 |
| Bradfield Commercial Limited | Wholesale & retail | 1994 |
| Bradfield GM Ltd | Other services | 2026 |
| Bradfield International Limited | Education | 2017 |
| Bradfield Manco Limited | Households | 2021 |
| Bradfield Motor Services Ltd | Extraterritorial | 2008 |
| Bradfield Print Services Ltd | Manufacturing | 2023 |
| Bradfield Southend CP Ltd | Hospitality | 2025 |
| Bradley Builders Construction Ltd | Construction | 2021 |
| Bradleyash Limited | Health & social care | 2012 |
| Brady’S Auto Repairs Ltd | Wholesale & retail | 2024 |
| Braidscentral Ltd | Other services | 2021 |
| Brain Affluence Limited | Professional & scientific | 2021 |
| Brainstorm Health Hub Ltd | Education | 2024 |
| Brainstorm Health Limited | Health & social care | 2013 |
| Braithwaite Reid Construction Ltd | Construction | 2022 |
| Bram Stoker Limited | Information & communication | 2012 |
| Brambleton Homes Ltd | Construction | 2021 |
| Bramley Green Limited | Information & communication | 2014 |
| Branchee Ltd | Wholesale & retail | 2021 |
| Branching OUT Tree Care Ltd | Administrative & support | 2025 |
| Brand Catalyst Ltd | Information & communication | 2026 |
| Brand Nudge Limited | Information & communication | 2019 |
| Brand Property Limited | Real estate | 2017 |
| Brand TG Ltd | Professional & scientific | 2011 |
| Brand X Solutions UK Ltd | Wholesale & retail | 2025 |
| BRAND195 Limited | Information & communication | 2024 |
| Brandish Consulting Limited | Professional & scientific | 2014 |
| Brandon & Harris Limited | Hospitality | 2013 |
| Brandon-Mareth Limited | Information & communication | 2014 |
| Brandorama Luxury Ltd | Wholesale & retail | 2025 |
| Brandy Designs Ltd | Manufacturing | 2025 |
| Brar Khote Ltd | Transport & logistics | 2026 |
| Brashlan Limited | Financial services | 2018 |
| Brasov Limited | Transport & logistics | 2015 |
| Brave New World Group Ltd | Information & communication | 2012 |
| Brave Star Investments Ltd | Hospitality | 2025 |
| Bravemech Services Limited | Construction | 2021 |
| Bravo Hospitality Ltd | Other services | 2018 |
| Bravo Travel Limited | Professional & scientific | 1999 |
| Bravour Limited | Arts & recreation | 1982 |
| Brawnj Limited | Wholesale & retail | 2021 |
| Braxted Investments Limited | Real estate | 2016 |
| Bray Culinary Village Limited | Hospitality | 2023 |
| Bray Market Management Ltd | Professional & scientific | 2024 |
| Bray Programme Consultancy Ltd | Administrative & support | 2016 |
| Bray Property Care Limited | Construction | 2024 |
| Brazenheath Management Limited | Households | 1991 |
| Brazil Skip Hire Limited | Water & waste | 2021 |
| BRD Search Limited | Administrative & support | 2026 |
| Breach Farm Brewing Ltd | Manufacturing | 2020 |
| Breadalbane Properties Limited | Real estate | 2017 |
| Breadmore Hopkins Ltd | Extraterritorial | 2010 |
| Break&Breathe Ltd | Professional & scientific | 2024 |
| Brechin Court (Management) Company Limited | Households | 1981 |
| Breedons Court Employers Limited | Professional & scientific | 2015 |
| Breethe Care Ltd | Health & social care | 2020 |
| Breeze at Home Limited | Wholesale & retail | 2025 |
| Breeze Health and Services Company Ltd | Professional & scientific | 2021 |
| Breffor Group Limited | Construction | 2020 |
| Brells Ltd | Professional & scientific | 2016 |
| Bremner Martin Consulting Ltd | Professional & scientific | 2020 |
| Brenna Services Ltd | Health & social care | 2018 |
| Brevan Howard Asset Management LLP | | 2002 |
| Brevan Howard Asset Management Services Limited | Financial services | 2017 |
| Brevan Howard Services Ltd | Administrative & support | 2002 |
| Brew Therapy Cafe Limited | Hospitality | 2024 |
| Brewery Court Theale Management Limited | Real estate | 2004 |
| Brian Dowding Court Limited | Households | 2011 |
| Briar Accounting Services Ltd | Professional & scientific | 2017 |
| Briarwood Property Limited | Real estate | 2021 |
| Brick & Mortar Management Group Limited | Households | 2018 |
| Brick Bonds Limited | Real estate | 2019 |
| Brick Huts Limited | Real estate | 2022 |
| Brickies Club Franchise-Reading Limited | Arts & recreation | 2024 |
| Bricks and Boundaries Ltd | Construction | 2025 |
| Bricktec Building Ltd | Construction | 2015 |
| Brico Ltd | Health & social care | 2010 |
| Bricolay Limited | Manufacturing | 2025 |
| Bridewell Bidco Limited | Financial services | 2021 |
| Bridewell Consulting Limited | Professional & scientific | 2017 |
| Bridewell Group Holdings Limited | Financial services | 2021 |
| Bridewell Group Limited | Financial services | 2021 |
| Bridge and Shield Technology Limited | Information & communication | 2023 |
| Bridge Audit Holdings Limited | Professional & scientific | 2025 |
| Bridge Auditing & Consultancy Services Limited | Professional & scientific | 2009 |
| Bridge Consultancy International Holdings Limited | Financial services | 2025 |
| Bridge Controls Limited | Administrative & support | 2003 |