| Bernard & Mary Sunley Limited | Extraterritorial | 1987 |
| Bernard Sunley & Sons Limited | Extraterritorial | 2004 |
| Berry Insight Limited | Professional & scientific | 2018 |
| Besim Latifaj Limited | Health & social care | 2016 |
| Bespoke Advisors Ltd | Professional & scientific | 2025 |
| Bespokehomejoinery Limited | Construction | 2018 |
| Best Physio Care Limited | Health & social care | 2013 |
| Besthands Ltd | Wholesale & retail | 2025 |
| BET Buy and Sell Ltd | Wholesale & retail | 2025 |
| Beta Verde Ltd | Real estate | 2020 |
| Betec Ltd | Construction | 1998 |
| Beth Bird Architecture Limited | Professional & scientific | 2025 |
| Better Place Holdings Ltd | Financial services | 2023 |
| Better Tax Futures Ltd | Information & communication | 2024 |
| Better Than Average Group Limited | Financial services | 2023 |
| Bettertrack Ltd | Information & communication | 2019 |
| Betvel Ltd | Professional & scientific | 2021 |
| Bevica Ltd | Information & communication | 2024 |
| Beyond Music Group Ltd | Information & communication | 2025 |
| Beyond Stone Ltd | Manufacturing | 2025 |
| BF Paintball Ltd | Arts & recreation | 2018 |
| Bhanot Enterprises Ltd | Real estate | 2025 |
| Big Baby Limited | Wholesale & retail | 2017 |
| Big Badger Theory Ltd | Information & communication | 2024 |
| Big Blade Consulting Ltd | Information & communication | 2018 |
| Big BUG Sports Limited | Professional & scientific | 1999 |
| Big Green BUS Cafe Ltd | Hospitality | 2026 |
| Big J'S Catering Limited | Hospitality | 2021 |
| Big Red Bear Ltd | Information & communication | 2007 |
| Bigpopa Limited | Transport & logistics | 2016 |
| Bikeright! Limited | Education | 2006 |
| Billecart - Salmon (UK) Limited | Wholesale & retail | 1995 |
| Billy H Limited | Professional & scientific | 2025 |
| Binky BUN Designs Ltd | Wholesale & retail | 2025 |
| Binney & Smith (Europe) Limited | Manufacturing | 1916 |
| Binny Trading Ltd | Financial services | 2025 |
| Biochron Ltd | Mining & quarrying | 2019 |
| Birch END Consulting Ltd | Administrative & support | 2025 |
| Birch Interiors Ltd | Construction | 2026 |
| Birchgrove (Banstead) LLP | | 2020 |
| Birchgrove (Chiswick) LLP | | 2022 |
| Birchgrove (Ewell) Acquisitions Limited | Health & social care | 2018 |
| Birchgrove (Ewell) LLP | | 2018 |
| Birchgrove (Godalming) Acquisitions Limited | Health & social care | 2020 |
| Birchgrove (Godalming) LLP | | 2020 |
| Birchgrove (Hampton CRT) LLP | | 2023 |
| Birchgrove (Leatherhead) LLP | | 2021 |
| Birchgrove (Mill Hill) LLP | | 2023 |
| Birchgrove (Sidcup) LLP | | 2016 |
| Birchgrove (Surrey) LLP | | 2018 |
| Birchgrove Care Limited | Health & social care | 2016 |
| Birchgrove Group LLP | | 2016 |
| Birchgrove Holdings LLP | | 2016 |
| Birchgrove Management Services Limited | Real estate | 2021 |
| Birchgrove Operations (Holdings) LLP | | 2016 |
| Birchgrove Operations Limited | Health & social care | 2016 |
| Birchgrove Services LLP | | 2016 |
| Birchgrove Team Limited | Real estate | 2021 |
| Birchway Services Limited | Administrative & support | 2003 |
| Birds EYE Limited | Manufacturing | 1938 |
| Bishams Court (Freehold) Company Limited | Households | 2009 |
| Bisley Enterprise Solutions Limited | Information & communication | 2021 |
| Bisley Homes Limited | Construction | 2005 |
| Bisley Removal Services Ltd | Transport & logistics | 2014 |
| Bitbridge Technologies Ltd | Information & communication | 2020 |
| Bivol Developments Ltd | Construction | 2023 |
| Bizimprovement Limited | Other services | 2020 |
| Bizworks Online Limited | Administrative & support | 2019 |
| Bjarke Ingels Co Ltd | Real estate | 2026 |
| BK Caravans Limited | Hospitality | 2025 |
| BK Enterprises Ltd | Wholesale & retail | 2018 |
| BK SIA Training Services Limited | Administrative & support | 2026 |
| Black Consulting Limited | Professional & scientific | 2024 |
| Black FAN Consulting Limited | Professional & scientific | 2016 |
| Black FAN Properties Limited | Real estate | 2016 |
| Black Heron Ltd | Information & communication | 2013 |
| Black Pearl Fish Bar Ltd | Hospitality | 2018 |
| Black Stone Puls Ltd | Hospitality | 2026 |
| Blackburn MIN Consulting Limited | Information & communication | 2013 |
| Blackbushe School of Flying 2012 Limited | Other services | 2012 |
| Blackbushe School of Flying Ltd | Other services | 2013 |
| Blackdown Avenue Residents Association Limited | Real estate | 2017 |
| Blackhorse Crescent Properties Ltd | Real estate | 2021 |
| Blackness Asset Limited | Financial services | 2018 |
| Blackpool Alpha Limited | Real estate | 2026 |
| Blacksquare Associates Ltd | Professional & scientific | 2019 |
| Blakedown Environment & Leisure Ltd | Construction | 1968 |
| Blakedown Landscapes (SE) Limited | Construction | 1990 |
| Blakedown Landscapes Limited | Extraterritorial | 1991 |
| Blakedown Limited | Construction | 2007 |
| Blakedown Sport & Play Limited | Construction | 2002 |
| Blakedown Sports Limited | Extraterritorial | 1981 |
| Blaze Point Heating Ltd | Manufacturing | 2022 |
| Blaze Recruitment Ltd | Professional & scientific | 2020 |
| Blazetek Ltd | Information & communication | 2021 |
| Blean Grove Penge Limited | Administrative & support | 2019 |
| Blenheim Gardens Ltd | Households | 2018 |
| BLF Events Ltd | Hospitality | 2024 |
| Bliss Beauty Boutique Ltd | Administrative & support | 2016 |
| Bliss Digital Consulting Limited | Information & communication | 2022 |