| Batty’S Abodes Ltd | Real estate | 2020 |
| Bayek Limited | Information & communication | 2019 |
| BBC Care Service Limited | Health & social care | 2019 |
| BD1044 Ltd | Extraterritorial | 2025 |
| BE UK Trader Ltd | Wholesale & retail | 2019 |
| Be.Haus Limited | Professional & scientific | 2025 |
| Beantale Coffee Ltd | Manufacturing | 2021 |
| Beau White Properties Limited | Real estate | 2018 |
| Beaumont FB Limited | Information & communication | 2026 |
| Beautyhubuk Ltd | Other services | 2023 |
| Beaver DAM Woodwork Ltd | Manufacturing | 2022 |
| Bebbington Plumbing & Heating Ltd | Construction | 2026 |
| BEE Asset Management Limited | Real estate | 1980 |
| BEE Properties Limited | Financial services | 1980 |
| BEE Securities Limited | Extraterritorial | 1981 |
| Beechwood Accountants Ltd | Professional & scientific | 2005 |
| Beetle Worx Ltd | Information & communication | 2026 |
| BEI Solutions Ltd | Administrative & support | 2024 |
| Bela Decorating Services Ltd | Construction | 2024 |
| Belenist Ltd | Wholesale & retail | 2021 |
| Bell Street Coffee Ltd | Hospitality | 2020 |
| Bellairs Construction Ltd | Construction | 2026 |
| Belmont Partners Management Company Limited | Households | 1990 |
| Belnomo Associates Ltd | Administrative & support | 2019 |
| Beneunder Limited | Other services | 2023 |
| Berenwood Properties Limited | Construction | 1968 |
| Berhills Consulting Limited | Professional & scientific | 2010 |
| Bespoke Cabins and Studios Ltd | Manufacturing | 2026 |
| Best Wines London Ltd | Wholesale & retail | 2011 |
| Best Wines Trading Limited | Wholesale & retail | 2020 |
| Betchworth Forge Limited | Manufacturing | 2016 |
| Betley Court 1960 Limited | Extraterritorial | 2014 |
| Bewarmer Limited | Wholesale & retail | 2013 |
| BEY Accountancy and Consultancy Ltd | Professional & scientific | 2022 |
| BEY Trade Ltd | Wholesale & retail | 2019 |
| Beyond the UK Ltd | Wholesale & retail | 2017 |
| Bfil Tech Ltd | Information & communication | 2019 |
| BFJ Media Limited | Information & communication | 2025 |
| BG Props Limited | Information & communication | 2013 |
| Bidhouse Ltd | Professional & scientific | 2023 |
| Big B Corporation UK Limited | Education | 2024 |
| Big Leisure Valeting Limited | Administrative & support | 2003 |
| Bigmore Nominees Ltd | Administrative & support | 2023 |
| Bigmore Payroll & Pensions Ltd | Administrative & support | 2021 |
| Bigmore Wills and Probate Limited | Other services | 2016 |
| Bimmms UK Ltd | Wholesale & retail | 2024 |
| Binaural Ltd | Information & communication | 2022 |
| Bioventure Works Ltd | Professional & scientific | 2024 |
| Biovetis Ltd | Manufacturing | 2025 |
| Bishopston Software Ltd | Professional & scientific | 2014 |
| Bison Windows Ltd | Construction | 2025 |
| Bitlink Limited | Information & communication | 2007 |
| Black Card Management Co Limited | Real estate | 2023 |
| Black Opal Properties Ltd | Real estate | 2024 |
| Blakfinch Productions Ltd | Information & communication | 2021 |
| Block 2 Block Property Services Limited | Administrative & support | 2006 |
| BLT Property Investments Ltd | Real estate | 2025 |
| Blue Cleaning Ltd | Administrative & support | 2020 |
| Blue Juice Recruitment Limited | Administrative & support | 2002 |
| Blue Motors Ltd | Wholesale & retail | 2024 |
| Blue Mountain Development Ltd | Professional & scientific | 2022 |
| Blue Orange Industries Ltd | Professional & scientific | 2020 |
| Bluefish Live Events Limited | Arts & recreation | 2009 |
| Bluemane Limited | Information & communication | 2021 |
| Blueplanc Ltd | Information & communication | 2018 |
| Bocca Knightsbridge Ltd | Hospitality | 2026 |
| Body Mechanics (UK) Limited | Other services | 2011 |
| Bodyshifters Mobile Limited | Wholesale & retail | 2025 |
| Bolanic Productions Limited | Arts & recreation | 2008 |
| Bollu Properties UK Ltd | Real estate | 2025 |
| Bona Tailoring Services (BTS) Ltd | Manufacturing | 2016 |
| Bonison (UK) Limited | Wholesale & retail | 2017 |
| Boot Creative Group Ltd | Information & communication | 2022 |
| Booze Spot Ltd | Wholesale & retail | 2026 |
| Borboleta Limited | Professional & scientific | 2019 |
| Bores Investment Limited | Energy | 2026 |
| Bores UK Holding Limited | Financial services | 2026 |
| Born Again Design Studio Ltd | Wholesale & retail | 2025 |
| Boss Robes Engineering Services Ltd | Professional & scientific | 2024 |
| Bowl Butler Limited | Hospitality | 2020 |
| Bradjay Limited | Health & social care | 2025 |
| Brahler UK Limited | Professional & scientific | 2021 |
| Bramley Projects Ltd | Professional & scientific | 2026 |
| Brandnew Films Ltd. | Information & communication | 1997 |
| Brandware Ltd | Wholesale & retail | 2020 |
| Brantwood Kids Play Ltd | Wholesale & retail | 2021 |
| Brava Investments Limited | Financial services | 2025 |
| Breathing Space Investments Ltd | Real estate | 2004 |
| Brick & Brace Ltd | Real estate | 2024 |
| Bridge Close Residents Company Limited | Households | 1988 |
| Bridge Dining Ltd | Hospitality | 2026 |
| Bridge Performance Consulting Ltd | Administrative & support | 2019 |
| Brient Financial Services Limited | Professional & scientific | 2025 |
| Bright Life Homes Limited | Real estate | 2014 |
| Brighter Beauty Group Ltd | Other services | 2019 |
| Brilliant-Removal.Com Limited | Transport & logistics | 2021 |
| Brimstone Builders Limited | Construction | 2025 |
| Britalia Auto Recovery Ltd | Wholesale & retail | 2021 |
| British Measurement and Testing Association | Other services | 1991 |
| Broadberry Care Services Ltd | Public administration | 2026 |