| BLL Logistics Limited | Transport & logistics | 2016 |
| Blofield Business Centre Limited | Real estate | 2006 |
| Blofield Consulting Ltd | Administrative & support | 2000 |
| Blofield Design Ltd | Professional & scientific | 2024 |
| Blofield Fish Bar Ltd | Hospitality | 2021 |
| Blofield Garden Machinery Centre Limited | Wholesale & retail | 2025 |
| Blofield Hall Management Company Ltd | Real estate | 2003 |
| Blofield Leisure Ltd. | Hospitality | 2017 |
| Blofield Nurseries Ltd | Agriculture & fishing | 1970 |
| Blofield Surgery Healthcare Limited | Extraterritorial | 2003 |
| Blonde on Blonde Direct Limited | Professional & scientific | 2000 |
| Blonde on Blonde Limited | Information & communication | 2000 |
| Blonde Salon Limited | Other services | 2007 |
| Bloom Construction Ltd | Construction | 2003 |
| Bloomcrown Limited | Administrative & support | 2010 |
| Bloomfield Residential Contractors Limited | Construction | 2021 |
| Bloompointe Ltd | Professional & scientific | 2026 |
| Blooms Transport Services Ltd | Transport & logistics | 2024 |
| Blossom and Gold Ltd | Extraterritorial | 2019 |
| Blossom and GRN Ltd | Wholesale & retail | 2024 |
| Blossom Jobs Limited | Administrative & support | 2021 |
| Bloxham Tipping Services Ltd | Transport & logistics | 2014 |
| BLS Engineering Services Limited | Professional & scientific | 2018 |
| BLS Plumbing and Heating Ltd | Construction | 2025 |
| BLU Consulting Limited | Information & communication | 2013 |
| BLU ORB Distribution Ltd | Wholesale & retail | 2020 |
| BLU ORB Ltd | Wholesale & retail | 2012 |
| BLU Sky Poultry Limited | Manufacturing | 2016 |
| Blue Agave Ltd | Hospitality | 2020 |
| Blue Belgravia Hospitality Limited | Professional & scientific | 2013 |
| Blue Burton Limited | Hospitality | 2019 |
| Blue Bury Farm Ltd | Agriculture & fishing | 2019 |
| Blue Consulting Limited | Professional & scientific | 2014 |
| Blue Crystal Property Management Ltd | Financial services | 2022 |
| Blue Damson Limited | Real estate | 2017 |
| Blue Delta Marketing Ltd | Information & communication | 2005 |
| Blue Dog Therapy Ltd | Professional & scientific | 2019 |
| Blue Dragon Holdings Ltd | Real estate | 2024 |
| Blue Energy Logistics Limited | Financial services | 2020 |
| Blue Heron Training Ltd | Education | 2023 |
| Blue Horizon Medical Ltd | Health & social care | 2022 |
| Blue Horizon Systems & Marketing Limited | Information & communication | 2015 |
| Blue Horizons Norfolk & Suffolk Homes Ltd | Real estate | 2024 |
| Blue Horizons Property Ltd | Real estate | 2021 |
| Blue House Investments Ltd | Real estate | 2014 |
| Blue Injection Moulding Supplies Limited | Manufacturing | 2007 |
| Blue Knot TOPCO1 Limited | Manufacturing | 2020 |
| Blue Light Repairs Ltd | Wholesale & retail | 2024 |
| Blue Monk Restaurant Ltd | Hospitality | 2019 |
| Blue Morph Limited | Health & social care | 2014 |
| Blue Note Construction Ltd | Construction | 2026 |
| Blue Pearl Photographic Ltd | Professional & scientific | 2013 |
| Blue Pigeon Productions Ltd | Information & communication | 2006 |
| Blue Raspberry Commerce Ltd | Administrative & support | 2022 |
| Blue Sand Medical Ltd | Health & social care | 2020 |
| Blue Sand Property Ltd | Real estate | 2026 |
| Blue Sapphire Homes Ltd | Real estate | 2017 |
| Blue Savannah Strategy Ltd | Professional & scientific | 2021 |
| Blue Shark Trading Limited | Wholesale & retail | 2018 |
| Blue Sky Graphics Ltd | Professional & scientific | 2010 |
| Blue Sky Home Improvements Ltd | Construction | 2026 |
| Blue Sky Leisure Limited | Hospitality | 2024 |
| Blue Sky Professional Development Ltd | Education | 2012 |
| Blue Stag Ltd | Professional & scientific | 2025 |
| Blue Synergy Consultancy Ltd | Administrative & support | 2013 |
| Blue Treacle Limited | Extraterritorial | 2003 |
| Blue Tycoon Developments Limited | Construction | 2019 |
| Blue Whale Ventures Ltd | Real estate | 2017 |
| Blue-Sphere Dynamics Limited | Professional & scientific | 2026 |
| Bluebell Osteopath Limited | Health & social care | 2014 |
| Bluebells Mental Health Training Ltd | Education | 2021 |
| Bluebird Land Developments Ltd | Construction | 2023 |
| Bluebird Wisdom Ltd | Professional & scientific | 2023 |
| Bluebox Attractions Ltd | Professional & scientific | 2019 |
| Bluebrick Assets & Property Ltd | Real estate | 2025 |
| Bluebridge Solutions Ltd | Information & communication | 2025 |
| Bluechip Accountants Ltd | Professional & scientific | 2024 |
| Bluegates Limited | Administrative & support | 2005 |
| Bluegates Property Ltd | Real estate | 2015 |
| Bluemiles Ltd | Real estate | 2007 |
| Bluepoint Investments Ltd | Real estate | 2020 |
| Blueprint Outcomes Ltd | Professional & scientific | 2025 |
| Blueseal Healthcare Limited | Health & social care | 2021 |
| Bluesky Project Services Ltd | Professional & scientific | 2015 |
| Bluesky UAV Ltd | Professional & scientific | 2016 |
| Bluespace Limited | Administrative & support | 2002 |
| Bluestone Cafe Ltd | Hospitality | 2025 |
| Bluestream Trading Co Limited | Energy | 2015 |
| Bluewater Consultancy and Training Limited | Education | 2022 |
| Bluewhalestudio Ltd | Manufacturing | 2021 |
| Bluey Bluey Limited | Wholesale & retail | 2022 |
| Blue’S NR3 Limited | Hospitality | 2021 |
| Blumify Ltd | Professional & scientific | 2025 |
| Blunsten Properties Ltd | Real estate | 2021 |
| Blush Studio by Beccy Ltd | Other services | 2023 |
| Blustorm Solutions Ltd | Professional & scientific | 2014 |
| BLW Holdings Limited | Financial services | 2023 |
| Blyburgate Barbers Ltd | Other services | 2024 |
| Blyth & Sons 2000 Company Limited | Real estate | 2000 |
| Blyth & Sons Limited | Other services | 1963 |