| Bello Clinical Research Ltd | Professional & scientific | 2024 |
| Bellum Active Ltd | Administrative & support | 2015 |
| Belmont Freehold Limited | Households | 2007 |
| Belmont Investment Enterprise Limited | Real estate | 2017 |
| Belmont Road Ltd | Real estate | 2019 |
| BEN & GUL Limited | Hospitality | 2017 |
| BEN Allen Rigging Ltd | Construction | 2022 |
| BEN Bullen Adventures Limited | Arts & recreation | 2013 |
| BEN Tunningley Limited | Administrative & support | 2013 |
| BEN Woodgate Music Limited | Administrative & support | 2016 |
| Benbro Investments Ltd | Financial services | 2025 |
| Benchmark Sashes Ltd | Construction | 2011 |
| Bendigo Wharf Management Company Limited | Real estate | 2003 |
| Bengal HUT Ltd | Hospitality | 2018 |
| Benji Recruitment Services Ltd | Administrative & support | 2021 |
| Beray Builders Ltd | Construction | 2004 |
| Bergair Limited | Administrative & support | 2006 |
| Berghmans FX Limited | Health & social care | 2025 |
| Berry Party Wall Consultancy Ltd | Professional & scientific | 2024 |
| Berrywell Entertainment Ltd | Information & communication | 2024 |
| Berrywell-Feed the Children | Other services | 2018 |
| Bespoke Homes South East Ltd | Construction | 2020 |
| Bespoke Staffing Solution Ltd | Administrative & support | 2024 |
| Best Buds Gardening Services Limited | Administrative & support | 2019 |
| Best Groupe Limited | Real estate | 2010 |
| Better Build Southern Limited | Construction | 2020 |
| Betterstaff Industrial & Commercial Recruitment Limited | Administrative & support | 2002 |
| Beulah Hook Limited | Professional & scientific | 2019 |
| Beville UK Limited | Construction | 2016 |
| Bexley Bites Ltd | Wholesale & retail | 2025 |
| Bexley Garden Annexes Ltd | Construction | 2024 |
| Bexley Garden Gyms Ltd | Construction | 2024 |
| Bexley Garden Offices Ltd | Construction | 2024 |
| Bexley Garden Rooms Ltd | Construction | 2021 |
| Bexley Hearing Centre Ltd | Wholesale & retail | 2021 |
| Bexley Light Car Club Limited | Arts & recreation | 1972 |
| Bexley Project Management Ltd | Professional & scientific | 2025 |
| Beyond the Pale ALE Houses Limited | Hospitality | 2019 |
| Beyond-E Interactive Ltd | Professional & scientific | 2019 |
| BFC International Food Centre Ltd | Wholesale & retail | 2023 |
| Bgbe Limited | Real estate | 2025 |
| BH Thai Limited | Hospitality | 2025 |
| BHM Catering Limited | Hospitality | 2024 |
| Bickley Trading Limited | Financial services | 2024 |
| Big APE Property Limited | Real estate | 2023 |
| Big Bird Care Ltd | Health & social care | 2026 |
| Big Breakfast Cafe Limited | Hospitality | 2015 |
| Bigold Limited | Information & communication | 2015 |
| Binary Finery Consulting Ltd | Other services | 2013 |
| Bindwell Bookbinders Limited | Administrative & support | 2004 |
| Binfinite Ltd. | Real estate | 2018 |
| Biodesic Ltd | Professional & scientific | 2016 |
| Bird N Blossom Ltd | Hospitality | 2026 |
| Birds of Ares Limited | Information & communication | 2019 |
| Birdsall Inns Holdings Limited | Financial services | 2014 |
| Birdsall Inns Limited | Hospitality | 2014 |
| Birkbeck Dentistry Limited | Health & social care | 2013 |
| Bishi Accountants & Co Ltd | Real estate | 2015 |
| Bishop’S Security Systems Ltd | Administrative & support | 2025 |
| Bite Apparel Limited | Wholesale & retail | 2022 |
| Bite Designs Limited | Professional & scientific | 2022 |
| Bitsleuth Ltd | Information & communication | 2025 |
| BK1 Ltd | Hospitality | 2021 |
| BL Home Building Services Limited | Construction | 2007 |
| BL Home Properties Limited | Real estate | 2022 |
| Black Bench Development Limited | Real estate | 2021 |
| Black Fathers Group Limited | Information & communication | 2025 |
| Black Raven Associates Limited | Professional & scientific | 2022 |
| Black Sail Software Limited | Information & communication | 2016 |
| Black Tail Trading UK Ltd | Wholesale & retail | 2011 |
| Black Thunder Pictures Ltd | Information & communication | 2023 |
| Blackbush (London) Limited | Wholesale & retail | 1983 |
| Blackfen Contracting Ltd | Professional & scientific | 2020 |
| Blackfen Culinary Ltd | Hospitality | 2025 |
| Blackfen Plumbing Ltd | Wholesale & retail | 2019 |
| Blackfen Private GP Ltd | Health & social care | 2025 |
| Blackfen Property Limited | Real estate | 2018 |
| Blackfen School for Girls | Education | 2012 |
| Blackfriars Staging Limited | Administrative & support | 2016 |
| Blackgemini Ltd | Professional & scientific | 2022 |
| Blackheath Bookmakers Ltd | Real estate | 2005 |
| Blackheath Maintenance Ltd | Construction | 2015 |
| Blackmums Limited | Information & communication | 2025 |
| Blackmun Security Limited | Administrative & support | 2016 |
| Blackwall Group Limited | Construction | 2019 |
| Blackwall Residential Limited | Real estate | 2019 |
| Blackwene Developments Limited | Construction | 2024 |
| Blakeleyrailservices Limited | Construction | 2014 |
| Blanket & Co. Ltd | Wholesale & retail | 2017 |
| Blend Makeup Ltd | Other services | 2015 |
| Blenheim Dash Limited | Financial services | 2022 |
| Bling My Home Ltd | Wholesale & retail | 2017 |
| BLING2O London Limited | Administrative & support | 2018 |
| Blink Properties Limited | Information & communication | 2013 |
| Blink Technical Limited | Professional & scientific | 2013 |
| Blink Telecom Limited | Wholesale & retail | 2009 |
| Blinkstrike Limited | Information & communication | 2025 |
| BLM Rail CON Limited | Professional & scientific | 2025 |
| Bloodfit Ltd | Information & communication | 2025 |
| Blooms Academy London Ltd | Other services | 2025 |