| B.Read Consultants Ltd | Administrative & support | 2025 |
| B5 Global Limited | Wholesale & retail | 2023 |
| Baby Explorers (Franchising) Ltd | Administrative & support | 2013 |
| Baby Explorers Ltd | Administrative & support | 2014 |
| Back 2 the Future Records Ltd | Construction | 2024 |
| Badger & FOX Limited | Arts & recreation | 2013 |
| Badger Construction Developments Ltd | Construction | 2016 |
| Bailey’S Cladding Ltd | Manufacturing | 2025 |
| Barclay Investments Limited | Real estate | 2003 |
| Barclay ROE Limited | Real estate | 1998 |
| Barefoot Growing CIC | Agriculture & fishing | 2022 |
| Basa Events Ltd | Other services | 2024 |
| Bayleys Building and Paving Contractors Ltd | Construction | 2018 |
| BB Charters Limited | Administrative & support | 2023 |
| BB Pet Supplies Limited | Wholesale & retail | 2019 |
| Bbsp Limited | Professional & scientific | 2020 |
| Bbvat Holdings Limited | Hospitality | 2009 |
| Bbvat Property Consultants Limited | Professional & scientific | 2009 |
| BEACHWOOD172 Landscapes Limited | Administrative & support | 2019 |
| Beau Property Design and Build Limited | Construction | 2020 |
| Beckgrove Flat Management Limited | Households | 2000 |
| BEE My Oyster Ltd | Wholesale & retail | 2022 |
| Beeches Farm Ecosystems Ltd | Agriculture & fishing | 2024 |
| Beechmont Lettings Limited | Real estate | 2017 |
| Beechmount Partners Limited | Professional & scientific | 2005 |
| Beetle Creative Limited | Professional & scientific | 2017 |
| Bells Builders Merchants (Dulwich) Limited | Wholesale & retail | 1970 |
| Belmound Investments Limited | Real estate | 1962 |
| Beltane 2 Limited | Real estate | 2023 |
| Beltane 2 Park Investment Limited | Real estate | 2025 |
| Beltane 2 Park LLP | | 2025 |
| Beltane Asset Management LLP | | 2009 |
| Beltane Astley Investment Limited | Real estate | 2025 |
| Beltane Astley LLP | | 2025 |
| Beltane Chester Street Investment Limited | Real estate | 2025 |
| Beltane Chester Street LLP | | 2025 |
| Beltane Connaught Investment LLP | | 2015 |
| Beltane Fitzroy Investment Limited | Real estate | 2024 |
| Beltane Fitzroy LLP | | 2024 |
| Beltane Limited | Real estate | 2010 |
| Beltane Marylebone Investment Limited | Real estate | 2020 |
| Beltane Marylebone LLP | | 2020 |
| Beltane MBH LLP | | 2019 |
| Beltane Notting Hill Investment Limited | Real estate | 2022 |
| Beltane Notting Hill LLP | | 2022 |
| Beltane OBS Investment Limited | Real estate | 2025 |
| Beltane OBS LLP | | 2025 |
| Beltane Services Limited | Administrative & support | 2014 |
| Beltane WTC Limited | Real estate | 2017 |
| Bemin Limited | Real estate | 2000 |
| Benchmark Cases Limited | Manufacturing | 2011 |
| Berthold Bauer VAT Consultants Limited | Professional & scientific | 2002 |
| Berzak Ltd | Hospitality | 2026 |
| Besa Connect Ltd | Professional & scientific | 2023 |
| BHR Media Ltd | Information & communication | 2021 |
| Billinghurst Racing Limited | Real estate | 1966 |
| BJH Properties Ltd | Real estate | 2026 |
| BKO Technologies Ltd | Construction | 2025 |
| Blacksmith Victoria Management Company Limited | Real estate | 2010 |
| Blackwoods Cheese Company Ltd | Manufacturing | 2015 |
| Bladon Healthcare Ltd | Health & social care | 2023 |
| Bladon Property Ltd | Construction | 2024 |
| Blooming Olives Day Nursery Limited | Health & social care | 2025 |
| Blooming Orchid Room Ltd | Other services | 2024 |
| Blower Hill Records Ltd | Arts & recreation | 2020 |
| Blush London Cleaning LLP | | 2015 |
| Bolebroke Gundogs Limited | Other services | 2019 |
| Botterill Sports Limited | Professional & scientific | 1977 |
| Bowden Property Investments Limited | Real estate | 2005 |
| Bower Bequest Trustee Company Limited | Administrative & support | 2007 |
| Bowlwonder Limited | Real estate | 2006 |
| Bracken Beads Limited | Wholesale & retail | 2026 |
| Bracken Escapes Limited | Other services | 2025 |
| Bradford Electrical (Edenbridge) Limited | Wholesale & retail | 1960 |
| Bradstock Consulting Engineers Ltd | Professional & scientific | 2023 |
| Bresser UK Ltd | Wholesale & retail | 2014 |
| Bridging the Gaps Enterprise Limited | Administrative & support | 2013 |
| Bridmark Limited | Agriculture & fishing | 1999 |
| Brightstone Engineering Ltd | Manufacturing | 2025 |
| Bristol Mastic MAN Ltd | Construction | 2020 |
| Broad Barrier Installations Limited | Construction | 2010 |
| Broadstone Concierge Limited | Construction | 2020 |
| Brockholt Consulting Limited | Professional & scientific | 2024 |
| Brookshire Capital LLP | | 2010 |
| Brookshire Investments Limited | Real estate | 2008 |
| Brookshire Partners LLP | | 2008 |
| Brother Film Co LLP | | 2010 |
| Brother Productions Limited | Information & communication | 2010 |
| Broxham Properties Ltd | Real estate | 2025 |
| Buff Browz Group Ltd | Wholesale & retail | 2023 |
| Bumblebee IT Solutions Ltd | Information & communication | 2019 |
| Bushy Wood Investments Ltd | Financial services | 2025 |
| Business Innovation Zone Ltd | Education | 2014 |
| BUSINESS2COMMUNITYLTD Ltd | Administrative & support | 2014 |
| Buy a KEG Ltd | Wholesale & retail | 2026 |
| Buzz Digital Limited | Information & communication | 2000 |
| C L V Limited | Professional & scientific | 1995 |
| C-Pro Direct Ltd. | Manufacturing | 1997 |
| Calculus Properties Ltd | Real estate | 2008 |
| Calculus Software Solutions Limited | Information & communication | 2000 |