| BDG GAS Ltd | Construction | 2026 |
| Bdpm Services Ltd | Construction | 2020 |
| BE Reputable Limited | Professional & scientific | 2026 |
| BE Social Management Ltd | Professional & scientific | 2024 |
| Beadles Joinery Limited | Manufacturing | 2005 |
| Beams Payroll Services Ltd | Administrative & support | 2023 |
| Beasley Electrical Maintenance Co Limited | Construction | 2005 |
| Beasley Legal Ltd | Professional & scientific | 2024 |
| Beau Tanning Lounge Ltd | Other services | 2025 |
| Beauty & Bloom (Kent) Ltd | Other services | 2026 |
| Becalm Care Ltd | Health & social care | 2023 |
| Becamas Limited | Wholesale & retail | 2024 |
| Beccamatt Limited | Construction | 2023 |
| Bedtime Stories Limited | Professional & scientific | 2006 |
| Beechdene Properties Ltd | Construction | 2020 |
| Beechenlea Consulting Ltd | Professional & scientific | 2018 |
| Beeshedschools Ltd | Education | 2025 |
| Belaku PVT Limited | Information & communication | 2021 |
| Bell Heritage Ltd | Wholesale & retail | 2026 |
| Bella Lindsay Ltd | Information & communication | 2026 |
| Belldray Lettings Ltd | Real estate | 2020 |
| Belldray Limited | Construction | 2016 |
| Belmond Consulting Limited | Administrative & support | 2020 |
| BEN Bacon Limited | Professional & scientific | 2016 |
| Benellen Property Estates Limited | Real estate | 2022 |
| Benicky Property Limited | Real estate | 2016 |
| Bennicks Cleaning Services Limited | Administrative & support | 2012 |
| Bentleys Interiors Limited | Construction | 2024 |
| Berkswell Recycling Limited | Water & waste | 2012 |
| Beskar Support Services Limited | Construction | 2023 |
| Bespoke England Tours Ltd | Administrative & support | 2020 |
| Bespoke Heating Services Ltd | Construction | 2017 |
| Best Roofs Roofing Ltd | Construction | 2024 |
| Betarandom Limited | Professional & scientific | 2019 |
| Better Health for YOU Ltd | Other services | 2026 |
| Bexley Steel Limited | Manufacturing | 1992 |
| BFJ Music Limited | Information & communication | 2023 |
| BG Property Investments Limited | Real estate | 2021 |
| BH International Ltd | Wholesale & retail | 2022 |
| Bickfield Property Investments Limited | Construction | 2014 |
| Big Dog Properties South East Limited | Real estate | 2021 |
| Billericay Business Hub Limited | Real estate | 2025 |
| Birchwood Aquatic Centre Ltd | Wholesale & retail | 2025 |
| Birdynumnum Two Ltd | Arts & recreation | 2021 |
| Birmingham Schools Partnership (Group) Limited | Financial services | 2003 |
| Birmingham Schools Partnership (Holdings) Limited | Financial services | 1999 |
| Birmingham Schools Partnership Limited | Construction | 1999 |
| Biro Fleabag Ltd | Financial services | 2021 |
| Bishop Akers LLP | | 2018 |
| Bixi Limited | Information & communication | 2000 |
| BJJ Consulting Ltd. | Information & communication | 2017 |
| Black Female Doctors UK CIC | Education | 2025 |
| Blackstone Estates Limited | Construction | 1986 |
| Blakeney Search Limited | Administrative & support | 2017 |
| Blenheim Forge Limited | Manufacturing | 2020 |
| Block and Mortar Limited | Real estate | 2022 |
| Bloom Box Flowers Ltd | Wholesale & retail | 2025 |
| BLS (South) Ltd | Professional & scientific | 2018 |
| Blue Cole Management Ltd | Professional & scientific | 2025 |
| Blue Iris Childcare Limited | Health & social care | 2023 |
| Blue Mane Management Ltd | Real estate | 2024 |
| Blue Mane Property Ltd | Construction | 2024 |
| Blue Raise Ltd | Wholesale & retail | 2026 |
| Blue Rock MS Limited | Administrative & support | 2022 |
| Blueprint Consultancy Solutions Limited | Professional & scientific | 2021 |
| Blueprint Property Services Ltd | Real estate | 2026 |
| BNB Cleaning Ltd | Administrative & support | 2026 |
| Boldcare Solutions Limited | Health & social care | 2015 |
| Bond Advisory & Consultancy Limited | Financial services | 2018 |
| Bournewood Sand & Gravel Limited | Mining & quarrying | 1999 |
| Bows Baby Boutique Ltd | Wholesale & retail | 2018 |
| Boxtex Ltd | Wholesale & retail | 2010 |
| BR Spice Swanley Limited | Hospitality | 2026 |
| Bradley Forge Limited | Professional & scientific | 2019 |
| Bree Construction (North) Limited | Construction | 1955 |
| Bree Construction (South) Limited | Construction | 1964 |
| Bree Construction (Woolwich) Limited | Construction | 2016 |
| Bree Group (North) Limited | Professional & scientific | 2011 |
| Bree Group (South) Limited | Professional & scientific | 2010 |
| Bree Holdings 2 Limited | Construction | 2016 |
| Bree Homes Group Limited | Professional & scientific | 2014 |
| Bree Homes Holdings Limited | Financial services | 2025 |
| Bree Living Limited | Professional & scientific | 2001 |
| Bree Property Development (North) Limited | Professional & scientific | 2005 |
| Bree Property Development (South) Limited | Professional & scientific | 1994 |
| Brian Hoolahan Limited | Professional & scientific | 2004 |
| Brick Link Consulting Limited | Professional & scientific | 2024 |
| Bridge IT Services Limited | Information & communication | 2025 |
| Bright Haven Consultancy Ltd | Administrative & support | 2009 |
| Bright Rock Ltd | Administrative & support | 2017 |
| Bright Transport Solutions Ltd | Manufacturing | 2023 |
| Brightside Cleaning Services Ltd | Administrative & support | 2023 |
| Broadback Security Ltd | Administrative & support | 2014 |
| Broadwalk Enterprises Ltd | Construction | 2020 |
| Brockdene Investments Limited | Extraterritorial | 2018 |
| Brockley Tile & Stone Limited | Construction | 2009 |
| Brooke House Consulting Limited | Professional & scientific | 2010 |
| Brown's Developments and Renovations Ltd | Real estate | 2024 |
| BRRM(24) Limited | Households | 2017 |
| Bruv Styling Ltd | Professional & scientific | 2020 |