| Bates Productions Ltd | Information & communication | 2021 |
| Bb@Home Ltd | Real estate | 2016 |
| Bddr Enterprises Limited | Information & communication | 2013 |
| Beachcourt Properties Limited | Real estate | 1998 |
| Beagleworks Limited | Information & communication | 2016 |
| Beaney Pearce Limited | Extraterritorial | 1991 |
| Beaumont Alexis HC Housing Limited | Hospitality | 2016 |
| Beaumont Alexis HC Limited | Hospitality | 2014 |
| Beaumont Alexis Housing Limited | Hospitality | 2016 |
| Beaumont Alexis Limited | Hospitality | 2009 |
| Becky Dell Music Academy Studios Limited | Education | 2019 |
| Bedesman Limited | Professional & scientific | 2022 |
| Beech Court Freehold Limited | Households | 2022 |
| Beechwood Group Limited | Financial services | 2024 |
| Beep Consulting Limited | Professional & scientific | 2017 |
| Beldhamland Limited | Extraterritorial | 1987 |
| Belico Technologies Ltd | Information & communication | 2022 |
| Bell Capital Ltd | Information & communication | 2015 |
| Bell Court (Hounslow) Residents Limited | Households | 1998 |
| Bell Investments Ltd | Real estate | 2022 |
| Bella - Digital Marketing Ltd | Professional & scientific | 2025 |
| Bellcom Technologies Ltd | Manufacturing | 2025 |
| Belloc Advisory Ltd | Professional & scientific | 2025 |
| Belsize Invest & Consult Ltd | Professional & scientific | 2015 |
| Bembridge & Osborne Holdings Limited | Financial services | 2024 |
| Benjy Brickz Ltd | Wholesale & retail | 2025 |
| Bentley & Price Surveyors Ltd | Professional & scientific | 2023 |
| Bertrade Ltd | Wholesale & retail | 2024 |
| Bespoke BBQ Kitchens Ltd | Professional & scientific | 2026 |
| Best Bengal Ltd | Hospitality | 2022 |
| Best Friends Club Ltd | Wholesale & retail | 2021 |
| Best Hungarian Store Ltd | Wholesale & retail | 2010 |
| Better Statistics CIC | Professional & scientific | 2021 |
| Bettersafe Products Ltd | Financial services | 2012 |
| Beverley House Management (Castelnau) Limited | Households | 2017 |
| Beynon Boyle Medical Ltd | Manufacturing | 2022 |
| BHM Solutions Limited | Professional & scientific | 2017 |
| BID Trawler UK Ltd | Information & communication | 2016 |
| Big P Ltd | Wholesale & retail | 2021 |
| Bill Oreilly Broadcast Sound Ltd | Information & communication | 2023 |
| Bills Food & Wine Ltd | Wholesale & retail | 2015 |
| Binneman Consultancy Ltd | Wholesale & retail | 2020 |
| Biolaw Solutions Limited | Professional & scientific | 2024 |
| Bioroll Limited | Wholesale & retail | 2010 |
| Biosportsfit Ltd | Professional & scientific | 2015 |
| Bird and the Stone Ltd | Information & communication | 2026 |
| Bitcoin-Academy Ltd | Professional & scientific | 2025 |
| Bizora Consulting Ltd | Information & communication | 2010 |
| BL3COACHING Ltd | Education | 2025 |
| Black Lives Natter CIC | Information & communication | 2024 |
| Blackmore House Limited | Professional & scientific | 1989 |
| Blackwood Risk Management Ltd | Administrative & support | 2022 |
| Blagdon House Estate Management Company Limited | Households | 2004 |
| Blanc Brasseries Limited | Hospitality | 2003 |
| Blandford House Freehold Company Limited | Real estate | 2003 |
| Blank Canvas Pictures Ltd | Information & communication | 2025 |
| Bliss Kitchen Produce Ltd | Manufacturing | 2025 |
| Blue Fire Theatre Company Ltd | Arts & recreation | 2017 |
| Blue Flame Systems Ltd | Professional & scientific | 2026 |
| Blue Gata Ltd | Professional & scientific | 2025 |
| Blue Haven Ltd | Information & communication | 2023 |
| Blue Heron Buildworks Ltd | Construction | 2025 |
| Blue Sky Thinking Consultancy Limited | Professional & scientific | 2007 |
| BMG Teddington Limited | Hospitality | 2016 |
| Boathousegroup.London Ltd | Professional & scientific | 2021 |
| Bobby Dazzlers Ltd | Other services | 2012 |
| Boffix & Co Accountancy Limited | Professional & scientific | 2016 |
| Boffix Accounts Limited | Professional & scientific | 2015 |
| Boffix Resources Ltd | Administrative & support | 2015 |
| Bohemian Minds Limited | Information & communication | 2025 |
| Bojest Limited | Wholesale & retail | 1998 |
| Boldli Ltd | Arts & recreation | 2024 |
| Bombaysmith Ltd | Professional & scientific | 2007 |
| Borrett Estates Limited | Real estate | 2021 |
| Boutique (Media) Production Services Limited | Information & communication | 2012 |
| BOW Tigers Limited | Real estate | 2006 |
| Bowery Lane Limited | Professional & scientific | 2023 |
| Bowman Advisory Limited | Professional & scientific | 2019 |
| Bowvision Engineering Ltd | Professional & scientific | 2018 |
| Bowvision Media Ltd | Information & communication | 2025 |
| Box IT by Design Limited | Wholesale & retail | 2014 |
| Boxed ETC Limited | Transport & logistics | 2022 |
| BR DLL Holdings Limited | Financial services | 2004 |
| BR DLL Limited | Extraterritorial | 1979 |
| Bradbury Stell Limited | Professional & scientific | 1996 |
| Bradbury Stell Probate Services Limited | Professional & scientific | 2019 |
| Bradfield Wentworth Property Limited | Professional & scientific | 2003 |
| Braemar Court Brentford (Freehold) Ltd | Real estate | 2022 |
| Braemar House Management Company Limited | Households | 1993 |
| Bramble & Associates Ltd | Administrative & support | 2024 |
| Brand Factor PTY Ltd | Professional & scientific | 2024 |
| Brand Worth Consulting Ltd | Professional & scientific | 2023 |
| Brave Butterflies Ltd | Professional & scientific | 2025 |
| Bredow Asset Co Ltd | Real estate | 2025 |
| Breeze Aircrew Solutions Limited | Administrative & support | 2021 |
| Bridge Developments (Twickenham) Ltd | Construction | 2018 |
| Bridge House (Manor Road) Residents Association Limited | Households | 1998 |
| Bridge House Residents' Management Co. Limited | Households | 1979 |
| Bridge the GAP Consulting Ltd | Information & communication | 2010 |
| Bridgecore Developments Limited | Construction | 2014 |