| Bibby Publishing Limited | Other services | 2007 |
| Bibliosoph Publishing Ltd | Information & communication | 2019 |
| Bickley Park Capital Ltd | Real estate | 2017 |
| Bidewell Properties Limited | Real estate | 2020 |
| Big BOY Events Limited | Information & communication | 2026 |
| Big Boys Pizza Maidstone Ltd | Hospitality | 2023 |
| Big Eco Bins Ltd | Water & waste | 2019 |
| Big Five Wine Company Ltd | Wholesale & retail | 2025 |
| Big M Promotions Ltd | Education | 2025 |
| Big Sisters Limited | Other services | 2022 |
| Big Soap Cleaning Ltd | Administrative & support | 2018 |
| Bigdog Film Productions Ltd | Information & communication | 2025 |
| BII Pipe Ltd | Wholesale & retail | 2021 |
| Biishops & Avalon Construction Ltd | Administrative & support | 2019 |
| Bilco Flow Ltd | Administrative & support | 2025 |
| Billa and Katpadi Ltd | Hospitality | 2025 |
| Billall Limited | Information & communication | 2023 |
| Billie Louise Limited | Arts & recreation | 2022 |
| Billington Invest Ltd | Real estate | 2022 |
| Billman Limited | Hospitality | 2019 |
| Billy Bleach Farrier Willow Tree Forge Ltd | Other services | 2016 |
| Billy the Event Limited | Administrative & support | 2025 |
| BIM Outsourcing Ltd | Professional & scientific | 2019 |
| Bimtex Accounting Limited | Professional & scientific | 2021 |
| Binghams Estates Ltd | Real estate | 2024 |
| Binjai Investments Limited | Financial services | 2017 |
| Bio-Med Stats 2022 Limited | Professional & scientific | 2019 |
| Biomed Career Hub Ltd | Education | 2026 |
| Biomotors Limited | Manufacturing | 2005 |
| Biosess Ltd | Construction | 2023 |
| Birds Family Funeral Directors Limited | Other services | 2013 |
| Birds Flyin' Ltd | Other services | 2026 |
| Birkby Developments Holdings Ltd | Real estate | 2024 |
| Birkby Developments Ltd | Real estate | 2023 |
| Birkby Homes Ltd | Real estate | 2026 |
| Birlcroft Solutions Limited | Professional & scientific | 2014 |
| Biro-B Trade Ltd | Construction | 2018 |
| Biscoveanu Services Ltd | Transport & logistics | 2020 |
| Bishop & Chhetri Ltd | Wholesale & retail | 2022 |
| Bishop & Rook UK Limited | Wholesale & retail | 2020 |
| Bishop Business Directions Limited | Professional & scientific | 2003 |
| Bishop Knight Construction Ltd | Construction | 2024 |
| Bisi Beauty Ltd | Other services | 2024 |
| Biskitt Ltd | Transport & logistics | 2021 |
| Bison Print Limited | Manufacturing | 2009 |
| Bister Architecture Limited | Professional & scientific | 2014 |
| Bitcoin Solutions Ltd | Transport & logistics | 2025 |
| Bitznfigs Ltd | Wholesale & retail | 2024 |
| Bivision Limited | Other services | 2013 |
| BIZ Media Limited | Information & communication | 1995 |
| Bizarbazaar Ltd | Wholesale & retail | 2025 |
| BJ Cesspool Services Ltd | Water & waste | 2010 |
| BJ Evans Haulage Ltd | Transport & logistics | 2021 |
| BJF Build Limited | Construction | 2011 |
| BJF Connections Ltd | Construction | 2007 |
| BJF Construction Limited | Construction | 2015 |
| BJF Energy Limited | Construction | 2013 |
| BJF Facilities Management Limited | Construction | 2015 |
| BJF Global Limited | Construction | 2015 |
| BJF Group Limited | Construction | 2015 |
| BJF Home Limited | Construction | 2011 |
| BJF Ltd | Construction | 2023 |
| BJF Organisation Limited | Financial services | 2011 |
| BJF Plant Limited | Construction | 2017 |
| BJF Services Limited | Construction | 2015 |
| BJM Developments Ltd | Real estate | 2020 |
| BJM UK Properties Ltd | Real estate | 2025 |
| BJW Computers Limited | Manufacturing | 1999 |
| BK Engineering Ltd | Construction | 2023 |
| BK Phones & Vapes Ltd | Wholesale & retail | 2026 |
| BK Pyrography Art Design Ltd | Wholesale & retail | 2023 |
| BK Steel Solutions Limited | Construction | 2020 |
| BL Carpentry Ltd | Construction | 2020 |
| BL Delivery Services Limited | Transport & logistics | 2016 |
| Black Box Colour Ltd | Information & communication | 2019 |
| Black by Joy Limited | Wholesale & retail | 2023 |
| Black LAB Music Ltd | Information & communication | 2024 |
| Black Lion Press Limited | Manufacturing | 1981 |
| Black Oak Consultants Ltd | Professional & scientific | 2026 |
| Black Oak Recruitment Ltd | Administrative & support | 2025 |
| Black Sand (Professional Services) Ltd | Professional & scientific | 2022 |
| Black TEE Club Ltd | Arts & recreation | 2026 |
| Blackbird Financial Ltd | Professional & scientific | 2010 |
| Blackfen Osteopathic Clinics Limited | Health & social care | 2003 |
| Blackmore Management Limited | Real estate | 2018 |
| Blackridge Tree Surgery Ltd | Agriculture & fishing | 2026 |
| Blacktap Ltd | Construction | 2010 |
| Blackwater Securities Limited | Construction | 2001 |
| Blackwater Services Limited | Administrative & support | 1998 |
| Blackwell Investment Company Limited | Households | 1961 |
| Blackwood Bayne Ltd | Professional & scientific | 2013 |
| Blaize Properties Ltd | Real estate | 2026 |
| Blaize Services Ltd | Construction | 2017 |
| Blake Commercial Consultancy Ltd | Professional & scientific | 2026 |
| Blankei Ltd | Wholesale & retail | 2019 |
| Blankspace Technology Limited | Professional & scientific | 2025 |
| Blazestar Solutions Ltd | Professional & scientific | 2024 |
| Blendini Ltd | Hospitality | 2009 |
| Blenheim Projects Limited | Professional & scientific | 2011 |
| Blessing by BLÉ Ltd | Hospitality | 2018 |