| Booba Ltd | Administrative & support | 2014 |
| Bookyourstylist Limited | Other services | 2024 |
| Boolean Logical Ltd | Information & communication | 2011 |
| Boom Property Business Ltd | Real estate | 2024 |
| Boons Media Limited | Information & communication | 2016 |
| Boots Boots Boots Limited | Wholesale & retail | 2008 |
| Borisa Ristic & Co Limited | Construction | 2015 |
| Boriva Limited | Information & communication | 2023 |
| Born 2 BE Free Ltd | Arts & recreation | 2025 |
| Bossa Brazil Limited | Professional & scientific | 1997 |
| Bossa Ltd | Professional & scientific | 2018 |
| Bossman Gems & Jewellery Limited | Manufacturing | 2011 |
| Boston Car Park Holdings Ltd | Transport & logistics | 2020 |
| Bothal Consultants Limited | Information & communication | 2001 |
| Boudi Fashion Limited | Wholesale & retail | 2015 |
| Boujee Catering Ltd | Hospitality | 2018 |
| Bounds Green Glass Ltd | Manufacturing | 2020 |
| Boundsie Broadcast Enterprise Ltd. | Information & communication | 2016 |
| Bourton Hall Limited | Administrative & support | 2019 |
| Boutique and Bakes Barnet Ltd | Wholesale & retail | 2025 |
| Boutique Donne Ltd | Wholesale & retail | 2024 |
| Boutique Spa Queensway Limited | Arts & recreation | 2012 |
| Bowmar Lodge Residents Association Limited | Households | 2003 |
| Bowquest Limited | Real estate | 1992 |
| Bowrovia Estates 2020 Limited | Real estate | 2021 |
| Boyes Sutton and Perry Solicitors Ltd | Professional & scientific | 2012 |
| Boys Toys Ltd | Administrative & support | 2024 |
| BP Building & Management Ltd | Construction | 2016 |
| BPM Fire Limited | Professional & scientific | 2022 |
| Bprime Limited | Manufacturing | 2014 |
| BR Design & Build Ltd | Construction | 2018 |
| BR Ground Maintenance Limited | Administrative & support | 2022 |
| Brabazon Property Limited | Real estate | 2021 |
| Bradley & Ginty Site Carpentry Limited | Construction | 2002 |
| Bradley Plumbing Ltd | Construction | 2019 |
| Braggs Clothing Ltd | Wholesale & retail | 2002 |
| Braille Translations Ltd | Other services | 2016 |
| Brainymill Advisors Limited | Information & communication | 2016 |
| Bramham Capital Ltd. | Financial services | 2015 |
| Bramhurst Ltd | Real estate | 2024 |
| Bramley Close Residents (Maisonettes & Garages) Limited | Households | 1996 |
| Bramwood Court Freehold Limited | Professional & scientific | 2004 |
| Brand Construction Limited | Administrative & support | 2023 |
| Brand New Shoes Limited | Professional & scientific | 2012 |
| Brandon Service Station Limited | Construction | 1962 |
| Brandpromo Ltd | Wholesale & retail | 2024 |
| Brandx LAB Ltd | Manufacturing | 2024 |
| Branksome Court Residents Association Limited | Households | 1999 |
| Branksome Dene Court Management Company Limited | Hospitality | 1998 |
| Branksome Dene Owners Limited | Households | 2017 |
| Bravo Limited | Information & communication | 1962 |
| Bravo Performers Ltd | Education | 2024 |
| Bravocharlie Technology Ltd | Information & communication | 2011 |
| Bread Port Ltd | Hospitality | 2011 |
| Breakspear Strategy Limited | Information & communication | 2024 |
| Breath Body Earth Ltd | Arts & recreation | 2023 |
| Brega Construction Ltd | Construction | 2026 |
| Brennan CC Ltd | Professional & scientific | 2023 |
| Brent Cross Office Furniture Limited | Wholesale & retail | 1996 |
| Brentwood Lodge (Management) Limited | Households | 1986 |
| Brescia Design Limited | Manufacturing | 2024 |
| Breskal Estates Limited | Real estate | 2021 |
| Brexel Limited | Extraterritorial | 1992 |
| BRI Contractors Ltd | Construction | 2015 |
| Brian Cottee Associates Limited | Manufacturing | 1980 |
| Brian Williams Hotels Limited | Professional & scientific | 2021 |
| Brian Yershon Distribution Services Limited | Wholesale & retail | 2010 |
| Brianco Services Limited | Real estate | 1943 |
| Brickman Insurance Services Ltd | Financial services | 2019 |
| Brickwood Construction Company Limited | Construction | 2003 |
| Bridge Court Management (Archway Road) Limited | Real estate | 1988 |
| BRIDGE06 Ltd | Information & communication | 2019 |
| Bridgedown Group Limited | Financial services | 2020 |
| Bridgedown Limited | Arts & recreation | 1989 |
| Bridgeside Estates Limited | Real estate | 1998 |
| Bridgewater IT Consulting Limited | Information & communication | 2015 |
| Bridgewater IT Services Limited | Information & communication | 2003 |
| Bridgeway Capital Financial Group Ltd | Financial services | 2024 |
| Brigade & Boardroom Limited | Professional & scientific | 2026 |
| Bright Beam Construction Ltd | Construction | 2025 |
| Bright House Trust Limited | Professional & scientific | 2012 |
| Bright Little Stars Barnet Limited | Education | 2018 |
| Bright Plans Design Ltd | Professional & scientific | 2025 |
| Brighter Star Limited | Real estate | 2019 |
| Brightway Controls Ltd | Information & communication | 2026 |
| Brim Westfield Stratford Ltd | Hospitality | 2022 |
| Brink Creative Limited | Professional & scientific | 2010 |
| Bristol Trading 2GO Limited | Hospitality | 2025 |
| Brix Investments Ltd | Real estate | 2020 |
| BRK Trading Limited | Wholesale & retail | 2012 |
| Brms London Ltd | Professional & scientific | 2025 |
| Broad Lane Fashions Ltd | Wholesale & retail | 2020 |
| Broadcast Audio Limited | Information & communication | 2007 |
| Broadcast Event Software Ltd | Information & communication | 2010 |
| Broadhaven Developments Ltd | Construction | 2015 |
| Broadhaven Estates Limited | Other services | 2009 |
| Broadhaven Holdings Limited | Other services | 2009 |
| Broadhaven Investments Limited | Real estate | 2014 |
| Broadhurst Associates Limited | Professional & scientific | 2008 |
| Broadway MH Ltd | Real estate | 2009 |