| Bideafford Properties Limited | Real estate | 2017 |
| Bielska Limited | Transport & logistics | 2022 |
| Bienvenue Supported Housing Services Ltd | Health & social care | 2024 |
| BIF Bruce Limited | Information & communication | 2017 |
| Big Beautiful World Publishing Ltd | Information & communication | 2026 |
| Big Black Dog Investments Limited | Financial services | 2017 |
| Big Blackcab Events Limited | Hospitality | 2017 |
| Big Brown Dog Limited | Professional & scientific | 2000 |
| Big Day Photography Limited | Information & communication | 2015 |
| Big Framed Shapes Ltd | Arts & recreation | 2020 |
| Big Horizons Limited | Real estate | 2020 |
| Big Kids' Table Limited | Information & communication | 2014 |
| Big Mama's Grill Ltd | Hospitality | 2025 |
| Big MAX Real Estate UK Limited | Real estate | 2025 |
| Big Mouth Gets Ltd. | Professional & scientific | 2015 |
| Big Mums Samosas Ltd | Hospitality | 2021 |
| Big Noir Limited | Information & communication | 2016 |
| Big Nose Comedy Productions Limited | Information & communication | 2025 |
| Big Play Productions Limited | Arts & recreation | 2024 |
| Big Rainy Street Ltd | Financial services | 2025 |
| Big Red Films Limited | Information & communication | 2012 |
| Big Red Scaffolding Services Ltd | Construction | 2019 |
| Big Rigs Pro Audio Limited | Professional & scientific | 2023 |
| Bigbazaruk Ltd | Wholesale & retail | 2019 |
| Bigbuzz Motors Private Limited | Wholesale & retail | 2026 |
| Bigeye Global Limited | Wholesale & retail | 2024 |
| Bigeye Solutions Limited | Real estate | 2024 |
| Bigger Than US CIC | Education | 2025 |
| Biggest Pictures Ltd | Manufacturing | 2025 |
| Bigo and Twigetti Records Ltd | Information & communication | 2022 |
| Bigrat Media Ltd | Information & communication | 2011 |
| Bigroof Ltd | Real estate | 2024 |
| BIGSIXP1 Ltd | Real estate | 2021 |
| Bigwood Developments Limited | Construction | 2013 |
| Bigwood Enterprises Limited | Real estate | 2003 |
| Bijash Engineering Services Limited | Wholesale & retail | 1984 |
| Bijaya & Pradeepa Properties Co. Ltd | Real estate | 2017 |
| Bijoubliss Limited | Wholesale & retail | 2025 |
| Biketastic Ltd | Other services | 2024 |
| Bikram (UK) Limited | Arts & recreation | 2012 |
| Bikram Yoga London Limited | Arts & recreation | 2009 |
| Bikter Tech Ltd | Professional & scientific | 2025 |
| Bil-Build Consultancy Ltd | Professional & scientific | 2013 |
| Bilad Ltd | Real estate | 2026 |
| Bilal DRY Fruits & VEG Ltd | Wholesale & retail | 2025 |
| Bilal Halal Meat Ltd | Wholesale & retail | 2021 |
| Bilan Brickwork Ltd | Construction | 2022 |
| Bilb Musical Holdings Limited | Arts & recreation | 2017 |
| Bilb Productions Limited | Information & communication | 2000 |
| Bilddit Limited | Wholesale & retail | 2023 |
| Bilddit Tech Limited | Wholesale & retail | 2023 |
| Bill the Baker Hillingdon Limited | Wholesale & retail | 2024 |
| Billionaire Baby Ltd | Wholesale & retail | 2019 |
| Billy Cooper Limited | Arts & recreation | 2017 |
| Bilsy Ltd | Professional & scientific | 2025 |
| Bilvantis Technologies Ltd | Information & communication | 2026 |
| BIM Construction Ltd | Construction | 2023 |
| BIM Install Pipe Ltd | Construction | 2023 |
| BIM Intelligence Ltd | Professional & scientific | 2026 |
| Bimbolus Limited | Health & social care | 2008 |
| Bimkak Consult Ltd | Administrative & support | 2017 |
| Binaj Limited | Real estate | 2022 |
| Binape Elevators UK Limited | Construction | 2017 |
| Binature Limited | Other services | 2012 |
| Binder Properties Limited | Other services | 2007 |
| Bindi (London) Limited | Extraterritorial | 1994 |
| Binks (Sales and Lettings) Limited | Real estate | 2000 |
| Binsina Investments Limited | Real estate | 2018 |
| Binsina Limited | Health & social care | 2006 |
| BIO Britware UK Ltd | Wholesale & retail | 2025 |
| BIO Global Industries Ltd | Wholesale & retail | 2013 |
| Biointellect Ltd | Administrative & support | 2025 |
| Bions Solutions Ltd | Professional & scientific | 2025 |
| Biopills Ltd | Wholesale & retail | 2020 |
| Biosenze Consulting Ltd | Professional & scientific | 2014 |
| Biotech Mechanical Limited | Construction | 2023 |
| Biowool Regen Ltd | Manufacturing | 2025 |
| Bipin Vyas & Co Limited | Professional & scientific | 2017 |
| Birch ROW Investments LLP | | 2019 |
| Birch Tree House Limited | Administrative & support | 2013 |
| Birdlip Lodges Limited | Hospitality | 2025 |
| Birks Nicola Holdings Limited | Hospitality | 2024 |
| Birlesik Textile Limited | Wholesale & retail | 2024 |
| Birma Enterprises Limited | Professional & scientific | 2007 |
| BIRO3 Limited | Financial services | 2026 |
| Biru Takeaway Ltd | Hospitality | 2023 |
| Biryani Express Ltd | Hospitality | 2014 |
| Biryani Kitchen Limited | Professional & scientific | 2023 |
| Biryani World Limited | Hospitality | 2025 |
| Bisamer Limited | Professional & scientific | 2014 |
| Bishan Construction Ltd | Construction | 2026 |
| Bishop Court Farm (Ventures) Limited | Construction | 2020 |
| Bishop Court Farm Limited | Agriculture & fishing | 2020 |
| Bishop KEN Montessori Nursery Limited | Health & social care | 2025 |
| Bishops Management Limited | Financial services | 1997 |
| Bishwan Ltd | Financial services | 2018 |
| Bismi Solutions Ltd | Information & communication | 2025 |
| Bismillah Catering Ltd | Hospitality | 2019 |
| Bismuth Consulting Limited | Real estate | 2026 |
| Bista Group Ltd | Wholesale & retail | 2025 |