| Beacon Retail Consulting Ltd | Real estate | 2021 |
| Beatcycle Ltd | Arts & recreation | 2021 |
| Beauclerc Limited | Real estate | 1989 |
| Beaumont Mews Management Limited | Households | 1996 |
| Beautiful Properties Group Ltd | Construction | 2016 |
| Beautyzon Limited | Wholesale & retail | 2018 |
| Beck and Call Commercial Limited | Administrative & support | 2016 |
| Beck and Call Direct Limited | Other services | 2010 |
| Become HER Ltd | Health & social care | 2026 |
| Bector Properties Limited | Real estate | 2021 |
| Bedford Court 79 Harrowdene Road Management Company Limited | Households | 1962 |
| Bedingfield Consultancy Limited | Information & communication | 2019 |
| Bediscoverable App Ltd | Information & communication | 2020 |
| Beechfield Investments Ltd | Real estate | 2018 |
| Beeta Engineering Ltd | Construction | 2014 |
| Beeta Innovations Ltd | Information & communication | 2025 |
| Beeuneeq Limited | Professional & scientific | 2009 |
| Behin Ltd | Transport & logistics | 2020 |
| Being Inclusive Research CIC | Professional & scientific | 2024 |
| Beirut Lane Ltd | Hospitality | 2026 |
| BEK Installations Ltd | Construction | 2018 |
| BEL Jour (UK) Ltd | Wholesale & retail | 2007 |
| Belgrave Financial Trading Ltd | Other services | 2009 |
| Belinda Shapps Limited | Health & social care | 2022 |
| Bell & SON Builders Limited | Construction | 2012 |
| Bell Computer Consultancy Limited | Information & communication | 1995 |
| Bella Pinner Ltd | Hospitality | 2026 |
| Bella Roma Pinner Ltd | Hospitality | 2023 |
| Bellasjade Ltd | Construction | 2025 |
| Bellgati & Co Ltd | Professional & scientific | 2026 |
| Belmont Healthcare Limited | Administrative & support | 1993 |
| Belmont Parkhill Limited | Health & social care | 1993 |
| Benfleet Systems Ltd | Administrative & support | 2008 |
| Bengal Delight Cuisine Limited | Hospitality | 2019 |
| Benjamin Cory Limited | Wholesale & retail | 1998 |
| Bentleys Properties Ltd | Real estate | 2013 |
| Benzie of Cowes Limited | Wholesale & retail | 1997 |
| Berko Office Limited | Real estate | 2011 |
| Berkshire Pharma Limited | Professional & scientific | 2022 |
| Berridge Bespoke Interiors Ltd | Manufacturing | 2026 |
| Berry Bartt Ltd | Wholesale & retail | 2020 |
| Bersted Properties Ltd | Real estate | 2019 |
| Bespoke Connections Ltd | Professional & scientific | 2012 |
| Bespoke Homes by Stephen Anthony Ltd | Construction | 2019 |
| Bespoke Investing Limited | Extraterritorial | 2025 |
| Bespoke Smile Academy Limited | Education | 2024 |
| Bespoke Smile Coaching Limited | Education | 2024 |
| Bespoke Smile Limited | Health & social care | 2018 |
| Bespoke Weddings Abroad Limited | Other services | 2007 |
| Best Option Properties Limited | Real estate | 2024 |
| Best Path Tuition Limited | Education | 2025 |
| Better Ears Ltd | Public administration | 2023 |
| Better Home Residential Limited | Real estate | 2025 |
| Better Nutrition Better YOU Limited | Health & social care | 2022 |
| Bettyo Services Limited | Hospitality | 2015 |
| Bexcrest Homes Limited | Construction | 2002 |
| BEYTAR49 Ltd | Other services | 2022 |
| BH Nails and Beauty Ltd | Other services | 2025 |
| Bhagavan Retail Limited | Wholesale & retail | 2026 |
| Bhanoh Developers Ltd | Construction | 2015 |
| Bhanu M & a Ltd | Professional & scientific | 2017 |
| Bharania Commercial Real Estate Ltd | Real estate | 2020 |
| Bharathi Consultancy Limited | Information & communication | 2011 |
| Bhardwaj Services Ltd | Information & communication | 2016 |
| Bharucha Ventures Limited | Professional & scientific | 2019 |
| Bhatt Orthopaedics Ltd | Health & social care | 2016 |
| Bhsla Trustees Limited | Administrative & support | 2023 |
| Bicycle Town Limited | Hospitality | 2017 |
| Bidesha Building Contractors Limited | Construction | 2005 |
| Bifrost Capital Ltd | Real estate | 2024 |
| Big Gains NO Pains Limited | Information & communication | 2008 |
| Big Noise Limited | Arts & recreation | 2019 |
| Big Planet Solutions Limited | Other services | 2014 |
| Bilton Developments Limited | Construction | 2025 |
| Bina Patel Limited | Professional & scientific | 2022 |
| Birchend Management Limited | Real estate | 2013 |
| Birmingham Self Drive Auto Centre Limited | | 1986 |
| Birsay Consulting Limited | Professional & scientific | 2015 |
| Birth,Beginnings and Beyond Ltd | Health & social care | 2008 |
| Bish Bash Productions Limited | Arts & recreation | 2003 |
| Bison Works Limited | Information & communication | 2024 |
| Bispecific Limited | Health & social care | 2020 |
| Bizhelp Network Limited | Professional & scientific | 2019 |
| BJ Brothers Limited | Real estate | 2022 |
| BKC Wholesale Ltd | Wholesale & retail | 2024 |
| BKG Pubs Limited | Hospitality | 2017 |
| BKR Limited | Wholesale & retail | 1996 |
| Black Oaks Investments Limited | Financial services | 2013 |
| Black Phoenix Games Ltd | Manufacturing | 2016 |
| Black Valley Limited | Professional & scientific | 2020 |
| Blackart Consultancy Limited | Professional & scientific | 2017 |
| Blackart Management (London) Limited | Professional & scientific | 2016 |
| Blackbolt Freehold Management Ltd | Households | 2010 |
| Blackbrick AUM Limited | Real estate | 2021 |
| Blackman Real Estate Limited | Real estate | 2016 |
| Blackmont Investments Limited | Construction | 2024 |
| Blackmont Properties Limited | Real estate | 2024 |
| Blackrock Property Trading Limited | Real estate | 2016 |
| Blackstar Equity Partners Limited | Construction | 2023 |
| Blackstock Kitchen LLP | | 2017 |