| Bibby Investments Limited | Real estate | 2025 |
| Bibby Irvine Homes Ltd | Real estate | 2021 |
| Bibby Irvine Ltd | Hospitality | 2017 |
| Bibelot Nook Limited | Wholesale & retail | 2023 |
| Biberchem Research Limited | Professional & scientific | 2017 |
| Bibliotheca Magica C.I.C. | Wholesale & retail | 2022 |
| BID IT UK Ltd | Extraterritorial | 2012 |
| Bidmen Ltd | Construction | 2020 |
| Bifanata Ltd | Hospitality | 2026 |
| Bifrost IT Solutions Ltd | Information & communication | 2017 |
| Big Bang People Solutions Ltd | Professional & scientific | 2024 |
| Big Bird Durham Ltd | Hospitality | 2024 |
| Big Boos PIZZAPOINT128 Ltd | Hospitality | 2026 |
| Big BOY Business Ltd | Professional & scientific | 2013 |
| Big Developments Ltd | Information & communication | 2022 |
| Big Finger Restaurant & Lounge Ltd | Hospitality | 2026 |
| Big Jigsaw Limited | Professional & scientific | 2010 |
| Big Lamp CIC | Information & communication | 2025 |
| Big MIC Ball Limited | Wholesale & retail | 2025 |
| Big Norm Ltd | Hospitality | 2025 |
| Big Red Show Ltd | Information & communication | 2024 |
| Big River Developments Limited | Real estate | 2005 |
| Big Screen Video Ltd | Wholesale & retail | 2023 |
| Bigfoot Networks Limited | Information & communication | 2014 |
| Bigg Market Chippy Limited | Hospitality | 2024 |
| Bigg Market Local Ltd | Wholesale & retail | 2025 |
| Biggie Smokes Vape House Limited | Wholesale & retail | 2025 |
| Bigmansdiary Ltd | Professional & scientific | 2025 |
| Bigpicture Learning Limited | Professional & scientific | 2017 |
| Bigswingingovaries Limited | Arts & recreation | 2021 |
| Bijoux Aesthetics Ltd | Other services | 2024 |
| Bikes-N-Co Limited | Wholesale & retail | 2010 |
| Bikesport (North East) Limited | Wholesale & retail | 2009 |
| Bikhan Homes Ltd | Real estate | 2025 |
| Bilal Foodstore Ltd | Wholesale & retail | 2020 |
| Bilals Group Ltd | Financial services | 2020 |
| Bilateral Design Ltd | Professional & scientific | 2018 |
| Bilcliffe Co. Ltd | Professional & scientific | 2023 |
| Bill Hewison Bespoke Homes Limited | Construction | 2005 |
| Billy Shiel Farne Islands Boats Limited | Transport & logistics | 2014 |
| Billy's Automotive Solutions Limited | Wholesale & retail | 2025 |
| BIM Technical Solutions Limited | Professional & scientific | 2015 |
| BIM Technologies (Europe) Limited | Information & communication | 2019 |
| Bimstore Limited | Information & communication | 2019 |
| BIN Clean North East Ltd | Administrative & support | 2026 |
| BIN Guard Limited | Administrative & support | 2010 |
| Bind CRM Limited | Administrative & support | 2020 |
| Bind Food Waste Innovation Community Interest Company | Hospitality | 2016 |
| Binderful Limited | Wholesale & retail | 2022 |
| Bindman Solicitors LLP | | 2016 |
| Bindoo's Kitchen Ltd | Hospitality | 2024 |
| Bingo Wings Limited | Arts & recreation | 2006 |
| Binkil Holdings Limited | Financial services | 2025 |
| Binkil Ltd | Water & waste | 2024 |
| Binnom Limited | Other services | 2024 |
| Binsk Consultancy Ltd | Information & communication | 2015 |
| BIO Labs Ltd | Wholesale & retail | 2026 |
| BIO Tech Pharma Limited | Information & communication | 2014 |
| Bio-Century Consulting Ltd | Professional & scientific | 2018 |
| Bio-Chem Pathways Limited | Education | 2025 |
| Biocow Environmental Services Limited | Professional & scientific | 2016 |
| Biodiverse Consulting Ltd | Professional & scientific | 2019 |
| Biofiber Technologies Limited | Professional & scientific | 1996 |
| Biofresh Group Limited | Wholesale & retail | 2011 |
| Biofrontera UK Limited | Wholesale & retail | 2022 |
| Biology Squad Ltd | Education | 2022 |
| Bionysus Limited | Professional & scientific | 2022 |
| Bioram Ireland Ltd | Information & communication | 2019 |
| Biosignatures Limited | Information & communication | 2007 |
| Biotech Improvements Group Ltd | Professional & scientific | 2020 |
| Birch Tree Northern Construction Limited | Construction | 2026 |
| Birch Tree Northern Limited | Construction | 2010 |
| Birchdove Developments Limited | Construction | 2024 |
| Birchtree Cattery Ltd | Other services | 2024 |
| Bird & Co Business Consultancy Ltd | Professional & scientific | 2025 |
| Bird House Properties Ltd | Real estate | 2015 |
| Bird in Bush Elsdon Ltd | Hospitality | 2026 |
| Birdhouse Group Ltd | Real estate | 2017 |
| Birdhousehomes Ltd | Real estate | 2022 |
| Birding Tour India Ltd | Administrative & support | 2023 |
| Birdview Aerial Ltd | Information & communication | 2016 |
| Birkenshaw Ltd | Construction | 2021 |
| Birketts Holdings Limited | Professional & scientific | 1996 |
| Birmingham Educational Investments Limited | Financial services | 2021 |
| Birmingham Passenger Transport Services Limited | Professional & scientific | 1994 |
| Birney Hall Properties Limited | Real estate | 2011 |
| Birth With YOU Ltd | Health & social care | 2021 |
| Birthbabe Media Ltd | Information & communication | 2026 |
| Biryani Express NCL Ltd | Hospitality | 2024 |
| Biryani Foods Limited | Hospitality | 2025 |
| BIS Consulting Ltd | Information & communication | 2025 |
| Bishop Bewick Catholic Education Trust | Education | 2011 |
| Bishop Cuthbert Area 6C Block 2 Management Limited | Real estate | 2005 |
| Bishop Cuthbert Area 7A Management Limited | Real estate | 2004 |
| Bishops Court (Durham) Management Company Limited | Real estate | 2005 |
| Bishops Park (Bishop Auckland) Managing Company Limited | Real estate | 2018 |
| Bishops Park (Management) Limited | Real estate | 2008 |
| Bisjid Multi-Ventures Ltd | Wholesale & retail | 2024 |
| Bismillah Accountants Limited | Professional & scientific | 2021 |
| Bismillah Newcastle Ltd | Real estate | 2018 |