| Bliss Chimney Sweeps Ltd | Construction | 2011 |
| Blissful Elixir Trading Co. Limited | Hospitality | 2025 |
| Blkvkg Building Services Ltd | Professional & scientific | 2026 |
| BLO I Ltd | Other services | 2019 |
| BLO II Ltd | Other services | 2017 |
| Block 6 Heritage Park RTM Company Limited | Households | 2016 |
| Block P Heritage Park Limited | Households | 2002 |
| Block Servicing Ltd | Manufacturing | 2025 |
| Block T Heritage Gate Freehold Company Ltd | Households | 2004 |
| Block Them & Bloom Limited | Information & communication | 2025 |
| Blocknize Technologies Ltd | Information & communication | 2021 |
| Blokes Boxes Limited | Wholesale & retail | 2023 |
| Blondynka Films Ltd | Information & communication | 2016 |
| Blonk Limited | Hospitality | 2011 |
| Bloodline Records Limited | Information & communication | 2024 |
| Bloom by ABA Ltd | Wholesale & retail | 2026 |
| Bloomin Lovely Florists Limited | Wholesale & retail | 2007 |
| Blooming Vyne Limited | Manufacturing | 2025 |
| Blooms and Blooms Ltd | Wholesale & retail | 2022 |
| Bloomsbury (Firepool) Management Company Limited | Households | 2015 |
| Bloomsbury Services Limited | Real estate | 2004 |
| Bloomstead Holdings Limited | Real estate | 2025 |
| Blossom & Co. Solutions Ltd | Administrative & support | 2025 |
| Blossom Marketing Agency Ltd | Professional & scientific | 2025 |
| BLP Scaffolding Ltd | Construction | 2023 |
| BLU Energy Group Limited | Extraterritorial | 2023 |
| BLU TEC Fasteners Limited | Manufacturing | 2015 |
| Blue Apple Contracting Ltd | Professional & scientific | 2011 |
| Blue Apple Garden Ltd | Wholesale & retail | 2026 |
| Blue Buddha Seeds Ltd | Manufacturing | 2019 |
| Blue Code Limited | Hospitality | 2016 |
| Blue Cross Healthcare Services Limited | Public administration | 2018 |
| Blue Dreamsworld Ltd | Information & communication | 2025 |
| Blue Flamingo Ltd | Professional & scientific | 2025 |
| Blue Line Traders Ltd | Wholesale & retail | 2018 |
| Blue Moon FOX Limited | Other services | 2018 |
| Blue Mountain Communications Limited | Professional & scientific | 2016 |
| Blue Nile W1 Limited | Professional & scientific | 2017 |
| Blue Orchid Venue Croydon Ltd | Hospitality | 2026 |
| Blue Phoenix Yachts Limited | Administrative & support | 2012 |
| Blue Power Solution Ltd | Construction | 2026 |
| Blue Sea Shipping Line Ltd | Transport & logistics | 2020 |
| Blue Skies Marketing Ltd | Professional & scientific | 2013 |
| Blue Star London Ltd | Other services | 2018 |
| Blue Streams Care Limited | Health & social care | 2018 |
| Blue Whales Holdings Limited | Financial services | 2022 |
| Blue Wolf Ltd | Manufacturing | 2015 |
| Blue&Rock Developments Ltd | Construction | 2025 |
| Bluebee Care Limited | Administrative & support | 2019 |
| Bluebell Chase Management Company Limited | Households | 2004 |
| Bluebell Entertainment Limited | Hospitality | 2022 |
| Bluebelle Consultancy Ltd | Professional & scientific | 2025 |
| Blueberry Pictures Ltd | Administrative & support | 2013 |
| Bluecrest (UK) Limited | Wholesale & retail | 1997 |
| Bluecrest Developments Ltd | Construction | 2020 |
| Bluecrest Properties UK Ltd | Real estate | 2019 |
| Bluemaho Associates Ltd | Professional & scientific | 2017 |
| Bluenerd Minecraft Limited | Information & communication | 2021 |
| Bluepeak Services Limited | Construction | 2024 |
| Bluepoint Holdings Limited | Real estate | 2019 |
| Bluepoint Management Company Limited | Households | 2003 |
| Blueprint and Threads Ltd | Wholesale & retail | 2026 |
| Blueprint Building & Maintenance Ltd | Construction | 2026 |
| Bluesky Brandworks Limited | Professional & scientific | 2025 |
| Bluesky Search Limited | Administrative & support | 2008 |
| Bluestar Consulting Ltd | Professional & scientific | 2024 |
| Bluetouch London CIC | Professional & scientific | 2020 |
| Bluewater GRP Limited | Real estate | 2023 |
| Bluewave 876 Group Ltd | Wholesale & retail | 2026 |
| Bluff Consultancy Limited | Administrative & support | 2019 |
| Bluhe Shire Investments Ltd | Financial services | 2024 |
| Blumarine Estate Limited | Construction | 2012 |
| Blumsom Limited | Wholesale & retail | 2018 |
| Bluvision Studios Ltd | Arts & recreation | 2025 |
| Blyth Wood Park Management Company Limited | Households | 1988 |
| Blyth Wood Park Property Company Limited | Households | 1996 |
| BM & RD Limited | Wholesale & retail | 2008 |
| BM Automove Ltd | Transport & logistics | 2026 |
| BM Family Investment Ltd | Real estate | 2021 |
| Bm&Rd Properties Limited | Real estate | 2025 |
| BMA Recruitment Ltd | Administrative & support | 2013 |
| Bmacks Healthcare Services Limited | Health & social care | 2021 |
| Bmars Properties (Old) Limited | Wholesale & retail | 2011 |
| BMD Projects Ltd | Construction | 2026 |
| Bmex Construction Ltd | Construction | 2016 |
| BMG Medics Ltd | Health & social care | 2017 |
| BMH Tutors Limited | Education | 2018 |
| Bmrr Properties Ltd | Real estate | 2024 |
| BMS Property Investments Ltd | Real estate | 2023 |
| BMU Holdings Ltd | Financial services | 2019 |
| BMV Autoworx Ltd | Wholesale & retail | 2024 |
| BN Connect Ltd | Administrative & support | 2025 |
| BN8 Ltd | Education | 2020 |
| BNB Drive Rentals Limited | Administrative & support | 2025 |
| BNG Asset Limited | Real estate | 2019 |
| BNK Retail Ltd | Wholesale & retail | 2024 |
| Bnkngcode Ltd | Real estate | 2018 |
| BNS Trades Ltd | Professional & scientific | 2025 |
| Boahene Best UK Ltd | Real estate | 2017 |
| Boardroom Bites Catering Co Ltd | Hospitality | 2024 |