| Besfa Assets Limited | Wholesale & retail | 2013 |
| Bespoke Billboards Limited | Professional & scientific | 2020 |
| Bespoke Grandeur Events Limited | Administrative & support | 2025 |
| Bespoke Intervention Services Limited | Health & social care | 2017 |
| Bespoke London Construction Limited | Construction | 2015 |
| Bespoke Skin Academy Ltd | Other services | 2023 |
| Best Choice Accountancy Ltd | Professional & scientific | 2008 |
| Best Choice Financial Services Ltd | Financial services | 2019 |
| Best Indian (Bromley) Ltd | Hospitality | 2025 |
| Bestfit Logic Ltd | Information & communication | 2019 |
| Bestfit Tailoring Limited | Other services | 2014 |
| Bestlondonservice Limited | Other services | 2013 |
| Betfan Limited | Information & communication | 2010 |
| Beth Green School of Arts Limited | Arts & recreation | 2024 |
| Bethsaida HR Ltd | Administrative & support | 2024 |
| Betsi at the Marsden | Health & social care | 2022 |
| Better Agile Ltd | Information & communication | 2019 |
| Better Doctor Training Ltd | Health & social care | 2012 |
| Better Health - Better Business 4JS Limited | Health & social care | 2016 |
| Better Home Plumbing Limited | Construction | 2023 |
| Better Living Partners Community Interest Company | Health & social care | 2020 |
| Bettyb Ltd | Professional & scientific | 2021 |
| Beverley Gate House Management Limited | Households | 2014 |
| Bevin Square (Wandsworth) Management Company Limited | Households | 1998 |
| Bevlin Limited | Health & social care | 2022 |
| Bexley Bears Preschool Limited | Education | 2019 |
| Bexley Trading Limited | Real estate | 2013 |
| Bexleyheath Bathrooms Limited | Professional & scientific | 2014 |
| Beyond Borders Consulting Ltd | Administrative & support | 2016 |
| Beyond Skin Foundation Ltd | Health & social care | 2017 |
| Beyond the Glass Consulting Limited | Professional & scientific | 2026 |
| BEZ Consulting Ltd | Administrative & support | 2016 |
| Bfch Limited | Arts & recreation | 2015 |
| BFL Talent Limited | Administrative & support | 2024 |
| BG Consulting Group Limited | Professional & scientific | 2002 |
| BG Maintenance Ltd | Administrative & support | 2025 |
| BGN Care Limited | Professional & scientific | 2024 |
| BGN Investments Ltd | Real estate | 2018 |
| BH Holding Group Limited | Financial services | 2019 |
| BHN Properties Limited | Real estate | 2017 |
| BHT Fire Protection Services Ltd | Public administration | 2004 |
| BHU Yachting Ltd | Extraterritorial | 2024 |
| BHV Financial Services Limited | Financial services | 2022 |
| Bibiji Limited | Wholesale & retail | 2023 |
| Bible Eclipse Limited | Information & communication | 2025 |
| Bibo Consultancy Limited | Professional & scientific | 2019 |
| Bickley Associates Limited | Construction | 2006 |
| Bickley Convenience Stores Ltd | Wholesale & retail | 2024 |
| Bickley Court Residents Association | Households | 1967 |
| Bickley Express Ltd | Wholesale & retail | 2026 |
| Bickley Fire & Security Specialists Ltd | Administrative & support | 2022 |
| Bickley Park Builders Limited | Construction | 2018 |
| Bickley Park Cricket Club Limited | Arts & recreation | 1956 |
| Bickley Rise Management Limited | Households | 2001 |
| Bickley Wellness LAB Ltd | Wholesale & retail | 2025 |
| BID Evolution Construct Ltd | Construction | 2019 |
| Biedronka Polish Delicatessen Ltd | Wholesale & retail | 2014 |
| Big Box Self Storage Ltd | Other services | 2026 |
| Big G Freehold Limited | Real estate | 2022 |
| Big Guyz Ltd | Wholesale & retail | 2025 |
| Big Johnny Ltd | Construction | 2018 |
| Big Padlock (Dartford) Limited | Other services | 2024 |
| Big Padlock (Self Storage) Limited | Real estate | 2016 |
| Big Padlock (UK) Ltd | Other services | 2011 |
| Big Padlock Alpenmile Ltd | Other services | 2025 |
| Big Padlock AYR Ltd | Other services | 2013 |
| Big Padlock Group Limited | Real estate | 1988 |
| Big Padlock Holdings Ltd | Real estate | 2017 |
| Big Padlock Limited | Other services | 2012 |
| Big Queer Time Machine Ltd | Information & communication | 2025 |
| Big Tree Landscape Contractors Limited | Administrative & support | 2010 |
| Bigfoot Youth Cycle Club Ltd | Arts & recreation | 2018 |
| Bigger Living Home Extensions Limited | Construction | 2026 |
| Biggoxx Ltd | Other services | 2016 |
| Bigminds Technology Solutions Limited | Information & communication | 2018 |
| Bigsexy Ltd | Wholesale & retail | 2026 |
| Bigsexyy Ltd | Wholesale & retail | 2025 |
| Bill & Mick's Ltd | Administrative & support | 2025 |
| Bill and Bonn Cakes Limited | Hospitality | 2012 |
| Billioncare Ltd | Health & social care | 2022 |
| Bills Botanicals Ltd | Other services | 2026 |
| Bimfire Consultants Limited | Construction | 2022 |
| Binicom Limited | Information & communication | 2002 |
| Binns Lifting Services Limited | Construction | 2024 |
| Bioguyver Ltd | Information & communication | 2018 |
| Bioresolve Limited | Health & social care | 2014 |
| Biovital UK Limited | Manufacturing | 2018 |
| Birch House (Kent) Ltd | Health & social care | 2024 |
| Birchall & Co (UK) Limited | Transport & logistics | 2019 |
| Birches (Durham Road) Management Limited | Administrative & support | 1975 |
| Bird in Hand PH Limited | Hospitality | 2023 |
| Bird Street Limited | Real estate | 2013 |
| Birka Online Ltd | Information & communication | 2021 |
| Biroda Real Estates Limited | Real estate | 2023 |
| Birthmark Studios Ltd | Wholesale & retail | 2026 |
| Bitfox Tech Ltd | Manufacturing | 2026 |
| Bitscale PVT Ltd | Professional & scientific | 2021 |
| Bitsy Tales Ltd | Information & communication | 2022 |
| Biznav Bromley Limited | Professional & scientific | 2015 |
| Biznav Group Limited | Financial services | 2018 |