| Breathe Digital Limited | Information & communication | 2022 |
| Breffo Ltd | Wholesale & retail | 2009 |
| Bregada Ltd | Construction | 2023 |
| Brent Beacon CIC | Health & social care | 2025 |
| Brent BIN Cleaning Company Limited | Administrative & support | 2005 |
| Brent Community Transport | Transport & logistics | 1980 |
| Brent Cross Studios Limited | Information & communication | 2021 |
| Brent CT Engineering Limited | Wholesale & retail | 2005 |
| Brent GP Alliance Ltd | Health & social care | 2026 |
| Brent GP Co-Operative Ltd | Health & social care | 2026 |
| Brent Local Express Ltd | Wholesale & retail | 2026 |
| Brent Parent Carer Forum Community Interest Company | Information & communication | 2019 |
| Brent Play Association | Education | 1999 |
| Brent Schools Partnership | Education | 2012 |
| Brentafricancaribbeancollective Ltd | Other services | 2024 |
| Brevon Limited | Wholesale & retail | 2025 |
| Brews Plumbing and Heating Ltd | Construction | 2025 |
| Brexville Limited | Wholesale & retail | 1990 |
| BRG Global Trading Limited | Professional & scientific | 2015 |
| Brian Lovell & Company Ltd | Construction | 2021 |
| Brickbird Consultants Limited | Information & communication | 2011 |
| Bridge Logistics Ltd | Transport & logistics | 2025 |
| Bridgepoint Alliance Ltd | Health & social care | 2020 |
| Bridgeva Ltd | Construction | 2014 |
| Bridgewater Building Management Ltd | Construction | 2014 |
| Bridgewater Court Freehold Company Limited | Households | 2015 |
| Bridgewater Court Management Limited | Households | 1977 |
| Bright Childcare Centre Ltd | Education | 2013 |
| Bright Dental Care Limited | Health & social care | 2017 |
| Bright Future Tutors Limited | Wholesale & retail | 2013 |
| Bright Gems Nursery Ltd | Health & social care | 2011 |
| Bright Secure Security Ltd | Wholesale & retail | 2025 |
| Bright Star Tuition Center Limited | Education | 2019 |
| Bright Vision Hub Limited | Administrative & support | 2025 |
| Bright World Property Maintenance Limited | Construction | 2020 |
| Brightcrest Limited | Health & social care | 2010 |
| Brighter Shine Ltd | Administrative & support | 2020 |
| Brighthands Services Ltd | Water & waste | 2025 |
| Brightstar Property Limited | Real estate | 2017 |
| Brightvale Properties Limited | Real estate | 2013 |
| Brightway Solutions Ltd | Wholesale & retail | 2015 |
| Brilliant Bespoke Holdings Ltd | Professional & scientific | 2020 |
| Brinthavanam Investment Ltd | Real estate | 2021 |
| Brinthavanam Property Investment Ltd | Real estate | 2025 |
| Brisk Trading Ltd | Transport & logistics | 2019 |
| Brislington Ltd | Hospitality | 2019 |
| Bristol Express Food Ltd | Hospitality | 2019 |
| Britania Carer Services Ltd | Health & social care | 2024 |
| Britano Ltd | Wholesale & retail | 2026 |
| Britanova Consulting Ltd | Other services | 2026 |
| Britcalls Ltd | Information & communication | 2021 |
| Britelite Retail Limited | Wholesale & retail | 2025 |
| Britglobe Technologies Ltd | Information & communication | 2024 |
| Britishsignlanguageschool Ltd | Education | 2025 |
| Britrpa Limited | Information & communication | 2020 |
| Britsteam Ltd | Hospitality | 2024 |
| Brittany Concepts Ltd | Manufacturing | 2020 |
| Brittany Cosmetics Ltd | Wholesale & retail | 2019 |
| Britwise Consultancy Ltd | Professional & scientific | 2022 |
| Broadcast Wave Ltd | Wholesale & retail | 2004 |
| Broadway Innovators Limited | Wholesale & retail | 2022 |
| Broadway Project Services Limited | Construction | 2012 |
| Broadwood Properties Limited | Real estate | 1999 |
| Broken Hill Investment Limited | Financial services | 2023 |
| Bromania Construction Limited | Construction | 2021 |
| Bromania UK Ltd | Construction | 2025 |
| Bronze Tanning and Beauty Salon Ltd | Other services | 2010 |
| Brook & Bricks Ltd | Hospitality | 2019 |
| Brooke Construction Limited | Manufacturing | 2019 |
| Brooksway Ltd | Real estate | 1999 |
| Bropharma Holding Limited | Financial services | 2019 |
| Brotherhood Capital Limited | Other services | 2023 |
| Brown Arrow Transport Limited | Administrative & support | 2020 |
| Brownshirt Limited | | 1969 |
| Broxim Ltd | Wholesale & retail | 2025 |
| Bruce J Reid Limited | Professional & scientific | 2014 |
| Bruci Home Ltd | Manufacturing | 2025 |
| Bruna Abreu Aesthetic Ltd | Other services | 2025 |
| Brush High Wycombe Ltd | Other services | 2014 |
| Brwn Ltd | Wholesale & retail | 2026 |
| Bryta Homes Property Limited | Real estate | 2004 |
| BS & L Peoperities Ltd | Real estate | 2025 |
| BS Automotive LP | | 2011 |
| BS Merry Limited | Hospitality | 2024 |
| BS Stratford Ltd | Hospitality | 2026 |
| Bsip Foods Ltd | Wholesale & retail | 2010 |
| Bsip Walthamstow Foods Ltd | Wholesale & retail | 2016 |
| BSO Holdings Ltd | Financial services | 2018 |
| BSY Autos Ltd | Wholesale & retail | 2023 |
| BT Propco Ltd | Real estate | 2021 |
| BT Tradeco Ltd | Financial services | 2020 |
| BTM Trading Limited | Wholesale & retail | 2005 |
| Btps Engineers Ltd | Construction | 2017 |
| BTR Group Limited | Financial services | 2025 |
| BTS Paving Ltd | Construction | 2019 |
| Bubsy London Limited | Wholesale & retail | 2019 |
| Buck Stalker Engineering Limited | Professional & scientific | 2025 |
| Buck Stalker United Engineering Ltd | Professional & scientific | 2025 |
| Bucket HAT Ltd | Information & communication | 2020 |
| Bucklesham Holdings Ltd | Real estate | 2020 |