| Blue Festive Ltd | Real estate | 2025 |
| Blue Ladder IT Services Ltd | Information & communication | 2021 |
| Blue Montage Communicates Limited | Professional & scientific | 2008 |
| Blue Pelican Limited | Administrative & support | 2001 |
| Blue Sky & Clouds Limited | Health & social care | 2005 |
| Blue Stream Capital Limited | Real estate | 2019 |
| Blue Traders Ltd | Financial services | 2019 |
| Blueband Accountancy Limited | Professional & scientific | 2013 |
| Bluebell Kent Ltd | Real estate | 2018 |
| Blueberry Farm Holdings Limited | Construction | 2020 |
| Blueberry Property Limited | Real estate | 2019 |
| Bluebird Film Production Limited | Information & communication | 2015 |
| Bluebox Self Storage (Property) Limited | Real estate | 2024 |
| Bluecrest Solutions Ltd | Arts & recreation | 2024 |
| Bluediamond Investors Limited | Financial services | 2022 |
| Bluemark Properties Ltd | Real estate | 2020 |
| Bluesky Citadel IT Consult Ltd | Information & communication | 2010 |
| Blueward LLP | | 2009 |
| Blur 7 Limited | Information & communication | 2008 |
| Blush and Co Limited | Other services | 2009 |
| Blyth Court (Bromley) RTM Company Limited | Households | 2025 |
| Blythen Company Ltd | Professional & scientific | 2024 |
| BM Brothers Ltd | Construction | 2018 |
| BM Golf Limited | Administrative & support | 2020 |
| Bmab Limited | Professional & scientific | 2015 |
| BMD Property Services Ltd | Real estate | 2017 |
| Bmhorses Ltd | Agriculture & fishing | 2022 |
| Bmpp Ltd | Construction | 2018 |
| Bobos Bubble World Ltd | Hospitality | 2025 |
| Bobos World Ltd | Hospitality | 2024 |
| Bobosanek Limited | Financial services | 2022 |
| Bodebright Consulting Ltd | Wholesale & retail | 2014 |
| Bodewell Homes Ltd | Real estate | 2019 |
| Bodeworth Associates Limited | Real estate | 2023 |
| Bodiam Court Management Company Limited | Households | 2003 |
| Bodigian & Company Limited | Extraterritorial | 1947 |
| Bodmas Consulting Limited | Professional & scientific | 2010 |
| Boffin Labs London Limited | Manufacturing | 2024 |
| BOI Marie Cakes Ltd | Manufacturing | 2023 |
| Bold Tony Ltd | Information & communication | 2020 |
| Bollom Consulting Limited | Financial services | 2022 |
| Bollom International Limited | Wholesale & retail | 2013 |
| Bollom Investments Limited | Financial services | 2022 |
| Bolt Electricians Ltd | Extraterritorial | 2020 |
| Bolt Lifts Ltd | Construction | 2022 |
| Bomba Kebab & Pizza Ltd | Hospitality | 2018 |
| Bond Capital Investment Limited | Real estate | 2021 |
| Boni Management Limited | Real estate | 2020 |
| Boniface Consulting Ltd | Information & communication | 2025 |
| Bonniuto's Italian Delicatessen Ltd | Hospitality | 2023 |
| Boogz on Show Ltd | Wholesale & retail | 2022 |
| Bookedsolid Ltd | Information & communication | 2024 |
| Bookkeeping Assistance Limited | Professional & scientific | 2013 |
| Boomsky Ltd | Wholesale & retail | 2020 |
| Booton Property Development Ltd | Construction | 2024 |
| Borek and Meze Limited | Hospitality | 2018 |
| Borkwood Lofts Limited | Construction | 2026 |
| Borkwood Park Management Limited | Households | 1966 |
| Boson Logistics & Automobiles Ltd | Wholesale & retail | 2019 |
| Boss Sport Horses Ltd | Agriculture & fishing | 2019 |
| Boté a Mano Limited | Administrative & support | 2015 |
| Boujee Boujee Ltd | Wholesale & retail | 2024 |
| Bournevale Properties Limited | Construction | 2016 |
| Bournex Ltd | Wholesale & retail | 2023 |
| Bower London Limited | Administrative & support | 2015 |
| Bows Beauty Training and Supplies Limited | Education | 2019 |
| Box Clever Energy Limited | Manufacturing | 2022 |
| Boxed EV Ltd | Manufacturing | 2026 |
| Boydell Associates Ltd | Information & communication | 2000 |
| BPD Design Services Ltd | Professional & scientific | 2011 |
| BPE Business Solutions Limited | Professional & scientific | 2009 |
| Bpsss Limited | Health & social care | 2023 |
| BPUK1 Ltd | Construction | 2022 |
| BPUK2 Ltd | Construction | 2022 |
| BPUK3 Ltd | Construction | 2024 |
| BPUK4 Ltd | Construction | 2024 |
| BPUK5 Ltd | Construction | 2024 |
| BPUK6 Ltd | Construction | 2024 |
| BPUK7 Ltd | Construction | 2024 |
| BR INK Tattoos Ltd | Other services | 2012 |
| BR6 Electrical Ltd | Construction | 2025 |
| Bracken Global Limited | Wholesale & retail | 2022 |
| Brainposh Limited | Information & communication | 2025 |
| Brambles Healthcare Limited | Health & social care | 2020 |
| Brandnewchoice Ltd | Information & communication | 2020 |
| Brands Supply Ltd | Administrative & support | 2022 |
| Brazils Cleaning Services Ltd | Administrative & support | 2025 |
| Bread & Butter Films Ltd | Administrative & support | 2007 |
| Breaking Thoughts Ltd. | Real estate | 2014 |
| Brecon Research Group Ltd | Other services | 2024 |
| Bredhurst & Autoroute Car Centres Limited | Wholesale & retail | 1998 |
| Breeding Endangered Species Trust | Extraterritorial | 2013 |
| Breeze (Southern) Limited | Wholesale & retail | 1992 |
| Breeze Voice Ltd | Information & communication | 2026 |
| Briar Resources Limited | Wholesale & retail | 2021 |
| Brick by Brick Pre-School Ltd | Education | 2025 |
| Brickbang Construction Limited | Construction | 2026 |
| Bridge Brickwork and Scaffolding Limited | Construction | 2019 |
| Bridge Construction and Developments Limited | Administrative & support | 2019 |
| Bridge Fire & Alarm Services Limited | Administrative & support | 2023 |