| B'S Valeting Centre Chelmsford Limited | Administrative & support | 2025 |
| B-Roofing Ltd | Construction | 2024 |
| B.A.A. Associates Limited | Real estate | 2000 |
| B.I.Z Construction Ltd | Construction | 2024 |
| B.M.A Associates Ltd | Other services | 2005 |
| B4B Ltd | Construction | 2024 |
| BA Investec Limited | Real estate | 2022 |
| Baah Property Investments Limited | Construction | 2025 |
| BAB Catering Ltd | Hospitality | 2024 |
| Babaya Photography Ltd | Professional & scientific | 2024 |
| Babba's Limited | Hospitality | 2023 |
| Babblehub Limited | Administrative & support | 2016 |
| Babs Professionals Limited | Public administration | 2023 |
| Babu Chinese Ltd | Education | 2023 |
| Babu Trading Ltd | Wholesale & retail | 2024 |
| Babywin Competitions Ltd | Wholesale & retail | 2025 |
| Back in the Day Vintage Ltd | Wholesale & retail | 2025 |
| Back in Time Taxi Limited | Transport & logistics | 2013 |
| Back to Life Medical Ltd | Health & social care | 2017 |
| Bacteria Detection Limited | Professional & scientific | 2016 |
| BAD N Bare Limited | Other services | 2021 |
| Bademina Property Limited | Real estate | 2025 |
| Badi Jewellery Ltd | Wholesale & retail | 2025 |
| BAG 4 U Limited | Wholesale & retail | 2014 |
| Baggionis Ltd | Construction | 2018 |
| Bags 7 Ltd | Real estate | 2021 |
| Bahai Original Limited | Other services | 2024 |
| Baharash Ltd | Extraterritorial | 2021 |
| Bahce 609 Ltd | Hospitality | 2023 |
| Bailey Structural Engineering Limited | Professional & scientific | 2024 |
| Bailey Traffic Management Ltd | Professional & scientific | 2024 |
| Baines Staffing Limited | Administrative & support | 2016 |
| Bajan Bite Box Ltd | Wholesale & retail | 2020 |
| Bake Consultancy Limited | Professional & scientific | 2012 |
| Baker Bhuiyan Ltd | Wholesale & retail | 2026 |
| Baker Crafts Limited | Wholesale & retail | 2022 |
| Baker Street Dixy Ltd | Hospitality | 2023 |
| Bako and Sons Ltd | Transport & logistics | 2015 |
| Baku 27 Limited | Hospitality | 2020 |
| BAL Repair Services Ltd | Other services | 2021 |
| Balagan Properties Ltd | Real estate | 2017 |
| Balas Civils Ltd | Construction | 2020 |
| Baldock Road Management Company Limited | Real estate | 1994 |
| Balind Creations Ltd | Health & social care | 2014 |
| Balkan Ember Ltd | Hospitality | 2023 |
| Baller Babies Limited | Education | 2023 |
| Balta Investment Limited | Real estate | 2024 |
| Balti Bhujon Ltd | Hospitality | 2022 |
| Bamboo & Grey Limited | Wholesale & retail | 2018 |
| Banbury RD Limited | Real estate | 2021 |
| Banica Transport Limited | Transport & logistics | 2018 |
| Bank of Beauty Ltd | Information & communication | 2021 |
| Bapary Ltd | Hospitality | 2023 |
| Bapcon Limited | Professional & scientific | 2013 |
| Bar 94 Ltd | Hospitality | 2022 |
| Barakah Business Services Ltd | Professional & scientific | 2025 |
| Barakah Kitchen Enfield Ltd | Hospitality | 2025 |
| Barakah Property Solutions Ltd | Real estate | 2025 |
| Baran Cihan Ltd | Hospitality | 2024 |
| Baran Enterprises Ltd | Real estate | 2020 |
| Baran Holdings Limited | Financial services | 2026 |
| Barbara Wootton Ltd | Health & social care | 2008 |
| Barbaros Logistics Ltd | Transport & logistics | 2025 |
| Barber LAB Academy Ltd | Education | 2024 |
| Barci Repairs Ltd | Construction | 2024 |
| Barclay Property Group Ltd | Hospitality | 2024 |
| Baris Tutoring Services Ltd | Education | 2021 |
| BARIS27 Ltd | Hospitality | 2026 |
| Barkbutler Ltd | Other services | 2026 |
| Barnavie Limited | Information & communication | 2019 |
| Barnet Sushi Ltd | Hospitality | 2019 |
| Barns Scaffold Ltd | Construction | 2025 |
| Barntc Medical Ltd | Health & social care | 2025 |
| Barre and Dirie Cars Ltd | Transport & logistics | 2025 |
| Barrj's Global Consulting Ltd | Health & social care | 2025 |
| Barrys Catering Ltd | Hospitality | 2025 |
| Bartonvale Ltd | Extraterritorial | 2006 |
| Bartoszewicz Tutor Classes Limited | Education | 2025 |
| Barworx Limited | Arts & recreation | 2024 |
| Barzel Fabrication Limited | Construction | 2020 |
| BAS Catering Limited | Hospitality | 2017 |
| Base Forest Limited | Information & communication | 2021 |
| Basfid Consults Ltd | Professional & scientific | 2011 |
| Bashika Beauty Ltd | Other services | 2025 |
| Basiduk Limited | Health & social care | 2016 |
| Basil Leaf Limited | Information & communication | 2014 |
| Bath & Henley Investments Ltd | Financial services | 2025 |
| Bathplan Ltd | Construction | 2019 |
| Batman Store Ltd | Wholesale & retail | 2025 |
| Batter & Co Holdings Ltd | Financial services | 2026 |
| Batter and Co Fish and Chips Ltd | Hospitality | 2024 |
| Batu Pipework UK Ltd | Wholesale & retail | 2023 |
| Baxter's Engineers Ltd | Construction | 2024 |
| Baxx Ventures Ltd | Health & social care | 2020 |
| Bayfront Limited | Real estate | 2018 |
| Baykse Limited | Construction | 2025 |
| Bayley Solutions Limited | Wholesale & retail | 2014 |
| Bayram Foods Ltd | Manufacturing | 2020 |
| Bayram Group Limited | Wholesale & retail | 2017 |
| Bayview House Ltd | Households | 2015 |