| Bond Management (INT) Limited | Arts & recreation | 2015 |
| Bonema Brasserie Limited | Hospitality | 2025 |
| Bones Production Limited | Wholesale & retail | 2023 |
| Bong Nguyen Limited | Other services | 2023 |
| Bonnie Clayton Consulting Limited | Administrative & support | 2010 |
| Bonnie Nails Ltd | Other services | 2023 |
| Bonsai by Nature Ltd | Agriculture & fishing | 2021 |
| Boother Properties Limited | Real estate | 2025 |
| Boothill Motorcycles Ltd | Wholesale & retail | 2013 |
| Boran London Ltd | Real estate | 2003 |
| Boranli Ltd | Hospitality | 2023 |
| Boray Properties Ltd | Real estate | 2026 |
| Borden Limited | Financial services | 2007 |
| Bored British Ltd | Wholesale & retail | 2024 |
| Boreland Electronic Engineers Limited | Administrative & support | 1984 |
| Boris Decorating Limited | Construction | 2022 |
| Borisova-Cleaning Services Limited | Administrative & support | 2008 |
| Borjgali Consultancy Ltd | Professional & scientific | 2023 |
| BORKATA70 Ltd | Construction | 2020 |
| Born to Build Lofts Ltd | Construction | 2023 |
| Borne by Nature UK Limited | Manufacturing | 2022 |
| Borough Group Ltd | Manufacturing | 2025 |
| Borufi Builders Limited | Construction | 2016 |
| Boss & Sons Limited | Real estate | 2006 |
| Boss Kebab Limited | Hospitality | 2026 |
| Bossa Nova Living Limited | Hospitality | 2022 |
| Bossman & Bradshaw Management Ltd | Real estate | 2022 |
| Bossman Estates Ltd | Real estate | 2019 |
| Bossman Group Ltd | Professional & scientific | 2022 |
| Bossy Construction Ltd | Construction | 2025 |
| Bostanci Legal Consultants Ltd | Administrative & support | 2011 |
| Boston Real Estate Ltd | Real estate | 2019 |
| Bosville Limited | Health & social care | 2003 |
| Bosw Ltd | Professional & scientific | 2024 |
| Botan Trading Ltd | Wholesale & retail | 2016 |
| Botany Medics Ltd. | Health & social care | 2014 |
| Boteva Ltd | Administrative & support | 2025 |
| Boulevard Investments Ltd | Real estate | 2024 |
| Boulevard Management Ltd | Real estate | 2025 |
| Boundary Service Station Limited | Wholesale & retail | 2008 |
| Bourne END Limited | Real estate | 2015 |
| Boutique Accommodation Ltd | Administrative & support | 2009 |
| Boutique Sayi Limited | Wholesale & retail | 2018 |
| Bouw Sub-Contr&Eu Workers Ltd | Construction | 2025 |
| BOW Kebab Limited | Hospitality | 2024 |
| Bowers Roofing Ltd | Construction | 2023 |
| Bowside Limited | Other services | 2014 |
| Box Box Media Ltd | Wholesale & retail | 2026 |
| Boxing Booth Limited | Administrative & support | 2011 |
| Boxwood Court Residents Company Limited | Households | 2007 |
| Bozkina Limited | Real estate | 2025 |
| Bozkurt Bookkeeping Limited | Professional & scientific | 2020 |
| BP Connections Limited | Administrative & support | 2005 |
| BPK Accountants and Tax Advisors Limited | Professional & scientific | 2025 |
| BPP Investments Limited | Financial services | 2016 |
| BPR Asia Ltd | Real estate | 2024 |
| Bradshaw & Mensah Ltd | Real estate | 2016 |
| Brags and Brams Holdings Ltd | Financial services | 2024 |
| Brags and Brams Ltd | Extraterritorial | 2024 |
| Brags and Brams Takeout Ltd | Hospitality | 2024 |
| Brain Audio Systems Limited | Manufacturing | 2010 |
| Brainy Care Recruitment Ltd | Administrative & support | 2019 |
| Brakendraper Ltd | Information & communication | 2025 |
| Bram SR Limited | Professional & scientific | 2023 |
| Brand Psychic Ltd | Information & communication | 2019 |
| BRANDED4UK Limited | Manufacturing | 2023 |
| Brave Construct Ltd | Construction | 2022 |
| Bravedale Limited | Administrative & support | 1977 |
| Brazilian Bikes Ltd | Wholesale & retail | 2025 |
| BRB Builders Ltd | Construction | 2023 |
| Breakin’ Bread Bakery Ltd | Manufacturing | 2025 |
| Breakthrough Property Services Limited | Real estate | 2012 |
| Breaky Box Ltd | Hospitality | 2026 |
| Brecan RO Ltd | Other services | 2025 |
| Brecan UK Ltd | Other services | 2023 |
| Brecon Art Ltd | Construction | 2018 |
| Breger Bambridge Limited | Construction | 2007 |
| Breger Bambridge Properties Limited | Real estate | 2012 |
| Brewstar Limited | Wholesale & retail | 2025 |
| Brian Paul (Secretaries) Limited | Professional & scientific | 2000 |
| Brian Paul Audit Ltd | Professional & scientific | 2025 |
| Brick & Olive Limited | Hospitality | 2017 |
| Brick House Store Ltd | Wholesale & retail | 2025 |
| Brick Lane Sheepskin Ltd | Wholesale & retail | 2016 |
| Brickhills Consulting Limited | Professional & scientific | 2019 |
| Brickyard Property Ltd | Real estate | 2021 |
| Bridge and Innovation Ltd | Education | 2026 |
| Bridge Food & Drink Ltd | Wholesale & retail | 2023 |
| Bridge Logistics Investments Limited | Real estate | 2025 |
| Bridgehouse Group Limited | Professional & scientific | 2009 |
| Bridgenhall Freehold Limited | Households | 2025 |
| Bridges & Bridges Property Limited | Real estate | 2016 |
| Bridgeview Ltd | Real estate | 2026 |
| Bridging Care Group CIC | Health & social care | 2026 |
| Bridging Finance 4U Ltd | Financial services | 2024 |
| Brigdeandinnovation CIC | Education | 2026 |
| Briggspolo Limited | Information & communication | 2015 |
| Bright Accountancy Limited | Professional & scientific | 2015 |
| Bright Deals Ltd | Wholesale & retail | 2024 |
| Bright Electrical Specialists Ltd | Construction | 2010 |