| Belgravia Property Development (London) Limited | Construction | 2011 |
| Belgravia Property Gasworks Limited | Construction | 2021 |
| Bell and Bell Inc Ltd | Arts & recreation | 2013 |
| Bell Container Trading Limited | Transport & logistics | 1983 |
| Belle Mare Properties Ltd | Real estate | 2021 |
| Bellecroft Limited | Financial services | 2011 |
| Bellis Homes (Southern) Ltd | Construction | 2015 |
| Bellis Homes Limited | Construction | 2014 |
| Bellis Trading Ltd | Construction | 2014 |
| Bellrose Solutions Ltd | Administrative & support | 2019 |
| Belmont Bond Limited | Information & communication | 2019 |
| Belvedere Residential Care Home Limited | Health & social care | 2023 |
| Bembridge Place RTM Company Limited | Real estate | 2026 |
| BEN Landscapes Ltd | Administrative & support | 2021 |
| BEN Macintyre Books Limited | Information & communication | 2014 |
| Benal Properties Ltd | Real estate | 2019 |
| Benaldoc Ltd | Health & social care | 2017 |
| Benata Ltd | Construction | 2019 |
| Bence Electrical Engineering Ltd | Construction | 2022 |
| Benchmark Digitol Ltd | Information & communication | 2009 |
| Benjy Adams Limited | Arts & recreation | 2025 |
| Bennu Law Limited | Professional & scientific | 2018 |
| Bennys Holdings Limited | Financial services | 2023 |
| Benson Dental Practice Limited | Health & social care | 2017 |
| Bentley Gardens Management Company Limited | Households | 2023 |
| Bentley Grove (Grotto) Ltd | Real estate | 2012 |
| Bentley Grove (Parkland) Ltd | Real estate | 2012 |
| Bentley Grove (Stanmore) Management Company Limited | Households | 2006 |
| Bentley Heights Limited | Wholesale & retail | 2017 |
| Bentley Orchard Interiors Ltd | Construction | 2010 |
| Bentley Place Residents Limited | Administrative & support | 2015 |
| Bentley-Leek Properties (JV3) Ltd | Construction | 2007 |
| Beoc Props Ltd | Arts & recreation | 2025 |
| Berry's Room Limited | Information & communication | 2012 |
| Besjoe Limited | Manufacturing | 2024 |
| Bespoke Chauffeur Hire Ltd | Other services | 2015 |
| Bespoke Photo Design Limited | Professional & scientific | 2010 |
| Bespoke Systemz Ltd | Professional & scientific | 2013 |
| Bespoke Window Furnishings Ltd | Construction | 2024 |
| Best "in" Kitchens Limited | Wholesale & retail | 1986 |
| Best Consulting Services Limited | Information & communication | 2000 |
| Best Cuts Barber Wrexham Ltd | Other services | 2023 |
| Best Look Cars Limited | Wholesale & retail | 2025 |
| Best Services Limited | Real estate | 1996 |
| Best Valeting Ltd | Administrative & support | 2022 |
| Bestcompare Ltd | Information & communication | 2021 |
| Bestir LDN Ltd | Wholesale & retail | 2021 |
| Beta Builders Ltd | Construction | 2023 |
| Betaboo Ltd | Wholesale & retail | 2023 |
| Bethany Allan Ltd | Information & communication | 2018 |
| Better Homes(Map) Ltd | Real estate | 2021 |
| Better Later Production Ltd | Information & communication | 2025 |
| Beval Limited | Construction | 2018 |
| Bewicks Amble Ltd | Hospitality | 2024 |
| Bexhill Care Centre Limited | Health & social care | 2015 |
| Bexwell Construction Limited | Construction | 1997 |
| Bexwell Developments (York Road) Ltd | Real estate | 2025 |
| Bexwell Developments Limited | Real estate | 2014 |
| Bexwell Homes Limited | Real estate | 2001 |
| Beyond Belief Brewing Company Limited | Manufacturing | 2021 |
| Bgf&I Ltd | Construction | 2023 |
| BH Practice FH Ltd | Real estate | 2025 |
| BHA PV Ltd | Wholesale & retail | 2019 |
| Bhavin Associates Limited | Health & social care | 2011 |
| BHE Limited | Real estate | 2005 |
| BHI Projects Ltd | Construction | 2017 |
| Bhikha-Barry Consultancy Ltd | Professional & scientific | 2019 |
| Bhuva Clinical Services Limited | Health & social care | 2026 |
| BHW Group Limited | Manufacturing | 1977 |
| Biadin Ltd | Information & communication | 2021 |
| Bicester Blind Centre Limited | Wholesale & retail | 2008 |
| Big Brand Discount Deals Limited | Wholesale & retail | 2019 |
| Big C'S Marine Limited | Professional & scientific | 1991 |
| Big City LLP | | 2012 |
| Big City Productions Limited | Arts & recreation | 2003 |
| Big Little London Limited | Professional & scientific | 2017 |
| Big Screen Transport Ltd | Administrative & support | 2022 |
| Big STU Productions Limited | Administrative & support | 2010 |
| Bigas Marketing Ltd | Professional & scientific | 2020 |
| Bill Granger Limited | Administrative & support | 2010 |
| Bimsophy Ltd | Professional & scientific | 2024 |
| BIN Sinai Leisure Group Limited | Financial services | 2022 |
| Bindys Consulting Limited | Information & communication | 2026 |
| Binmile Technologies Limited | Information & communication | 2021 |
| BIO Dima Limited | Hospitality | 2017 |
| Birkin & Couper Ltd | Manufacturing | 2022 |
| Birklands Management Limited | Households | 1987 |
| Birmingham Buffet Ltd | Real estate | 2018 |
| Bisham Court Management Limited | Households | 1983 |
| Bishop Blaize Richmond Limited | Hospitality | 2023 |
| Bishopsgrange Whisky Club Limited | Wholesale & retail | 2023 |
| Bisoc Mechanical Services Ltd | Construction | 2020 |
| Bitkarma Limited | Professional & scientific | 2014 |
| Bitluma Ltd | Wholesale & retail | 2025 |
| Bits Bobs and ODD Jobs Limited | Administrative & support | 2012 |
| Bittacy Land Limited | Real estate | 2020 |
| Biza Limited | Hospitality | 2005 |
| Bizifind Limited | Information & communication | 2018 |
| Bizmatrix (U.K.) Limited | Wholesale & retail | 2017 |
| Bizmide Consulting Limited | Information & communication | 2015 |