| Azimis Pizza Ltd | Hospitality | 2026 |
| Azimuth Music Production Ltd | Information & communication | 2021 |
| Azora Homes Limited | Real estate | 2025 |
| Aztec Services (UK) Limited | Manufacturing | 2011 |
| Azzurien Ltd | Hospitality | 1996 |
| B & E Car Services Limited | Wholesale & retail | 2020 |
| B & H 828 Motors Ltd | Wholesale & retail | 2024 |
| B & I Cleaning Services Ltd | Administrative & support | 2025 |
| B & R Enterprise Limited | Administrative & support | 1998 |
| B and K Trading Ltd | Wholesale & retail | 2020 |
| B Comms Solutions Limited | Information & communication | 2020 |
| B M Cadle Renovations Limited | Construction | 2002 |
| B Management Ltd | Construction | 2023 |
| B Other Wise Ltd | Professional & scientific | 2020 |
| B S Kaler Builders Ltd | Construction | 2020 |
| B&G Blackhole Energy Ltd | Construction | 2025 |
| B&I Interiors Ltd | Professional & scientific | 2022 |
| B&J Waste Limited | Water & waste | 2023 |
| B&S Design and Build Holdings Ltd | Other services | 2021 |
| B. Prem Limited | Households | 2026 |
| B.A.M. Security Services Ltd | Construction | 2010 |
| B.A.S.Executive Ltd | Transport & logistics | 2012 |
| B.Ec. Autos Ltd | Wholesale & retail | 2024 |
| B.H.& I.Baldwin Limited | Real estate | 1960 |
| B.R.I.K. Properties Ltd | Real estate | 2009 |
| B.V. Drylining Ltd | Construction | 2020 |
| B2 Executive Cars Ltd | Transport & logistics | 2022 |
| B5 Consultancy Limited | Other services | 2019 |
| BAA Transport Ltd | Transport & logistics | 2025 |
| Baaloo Ltd. | Information & communication | 2023 |
| Baani's Ceramic World Ltd | Manufacturing | 2024 |
| Baani’S Property Developments Ltd | Real estate | 2026 |
| BAB Developments Limited | Construction | 2022 |
| Babeczka Ltd | Professional & scientific | 2022 |
| Babu & Sons Limited | Real estate | 2017 |
| Back in Sync Ltd | Other services | 2024 |
| Badbury Hill Farm Limited | Agriculture & fishing | 2013 |
| Baden Management Systems Ltd | Professional & scientific | 2025 |
| Badgers Auctions Ltd | Wholesale & retail | 2020 |
| Badgers Croft Limited | Construction | 2003 |
| Badhan-Gill Investments Limited | Real estate | 2017 |
| Badiyani & Partners Limited | Information & communication | 2025 |
| Badshahi Kitchen Corner Ltd | Hospitality | 2025 |
| Badshahi Kitchen Express Ltd | Hospitality | 2026 |
| Baguettes & More Limited | Hospitality | 2020 |
| Bahama Windows Limited | Construction | 1970 |
| Bahawal Sons Ltd | Wholesale & retail | 2024 |
| Bailey Shaw Consultants Ltd | Administrative & support | 2023 |
| Bains & Bains Investments Limited | Real estate | 2024 |
| Bajinc Ltd | Real estate | 2014 |
| Bajwa Build & 3D Design Ltd | Construction | 2022 |
| Bajwa Property Ltd | Real estate | 2022 |
| Baked Bites Ltd | Real estate | 2014 |
| Bakerwood Construction Limited | Construction | 2003 |
| BAL COURIER1 Ltd | Transport & logistics | 2023 |
| Balayage Baby Ltd | Other services | 2025 |
| Baldwin Construction (HW) Limited | Construction | 2023 |
| Balemoor Limited | Households | 2002 |
| Balochmotorgroup Ltd | Wholesale & retail | 2023 |
| BAM Catering Ltd | Hospitality | 2019 |
| BAM Tech Ltd | Wholesale & retail | 2020 |
| Bamboo Property Developments Limited | Households | 2026 |
| Bamboo Property Limited | Real estate | 2016 |
| Bambox Ltd | Wholesale & retail | 2018 |
| Bamford Executive Services Ltd | Transport & logistics | 2026 |
| Banat Consulting Ltd | Health & social care | 2023 |
| Banat Holdings Ltd | Financial services | 2023 |
| Bangladesh Club UK Ltd | Information & communication | 2024 |
| Banner Property Services Limited | Real estate | 1983 |
| Bansil Technik Ltd | Health & social care | 2023 |
| Bantry Building Services Ltd | Administrative & support | 2012 |
| Baobab Independent Together CIC | Education | 2025 |
| Baraka Ltd | Wholesale & retail | 2026 |
| Barakah Community Hub Ltd | Health & social care | 2026 |
| BARAKAH101 Ltd | Education | 2025 |
| Barbara Pylko Limited | Health & social care | 2013 |
| Barbarian Grill Ltd | Hospitality | 2016 |
| Barbers Time Ltd | Information & communication | 2026 |
| Bargains Emporium Ltd | Wholesale & retail | 2026 |
| Barge Waste Management Limited | Other services | 1993 |
| Barhams Financial Services Limited | Financial services | 2001 |
| Barker Butts Lane Management Company Limited | Extraterritorial | 2007 |
| Barking Barbers Group Limited | Other services | 2015 |
| Barlow Hairdressers Limited | Other services | 2003 |
| Barnes Garden Outbuildings Ltd | Construction | 2012 |
| Barnett & Merriman Limited | Financial services | 2020 |
| Barney's Biscuit Boxes Limited | Manufacturing | 2014 |
| Barnlea Apartments Ltd | Real estate | 2018 |
| Barnsbury Investments Limited | Real estate | 1998 |
| Barrett Control Systems Ltd | Construction | 2020 |
| Barrettec Limited | Information & communication | 2004 |
| Barrosa Developments Ltd | Construction | 2025 |
| Barrosa Holdings Ltd | Construction | 2025 |
| Barrosa Lettings Ltd | Real estate | 2025 |
| Barrys Accountants Limited | Professional & scientific | 2005 |
| Barton Property Developments Limited | Hospitality | 2002 |
| Barwala Events Limited | Hospitality | 2026 |
| BAS Caribbean Food Ltd | Wholesale & retail | 2020 |
| BAS Engineering Ltd | Wholesale & retail | 2018 |
| BAS Enterprises Ltd | Hospitality | 2024 |