| Beltfed Wargaming & Bears Bunker Ltd | Wholesale & retail | 2025 |
| BEN Davison Videography Ltd | Professional & scientific | 2021 |
| Beni's Art Ltd | Arts & recreation | 2019 |
| Benny Side Limited | Financial services | 2024 |
| Benson Plumbing and Heating Ltd | Construction | 2013 |
| Bensway Surveys Ltd | Construction | 2014 |
| Bentley's North Shore Limited | Hospitality | 2022 |
| Berrico Ltd | Extraterritorial | 2022 |
| Berry Capital Group Ltd | Professional & scientific | 2025 |
| Bespoke Motor Works Ltd | Wholesale & retail | 2014 |
| Bespoke Renovations (NE) Ltd | Administrative & support | 2015 |
| Bespoke Trades Construction Ltd | Construction | 2022 |
| Best Life Healthcare Ltd | Health & social care | 2008 |
| Best Square Pizza 4U Ltd | Hospitality | 2025 |
| Bettley Limited | Information & communication | 2009 |
| Bettys Close Developments Limited | Construction | 2015 |
| Betty’S Boudoir Ltd | Wholesale & retail | 2018 |
| Beulah Afro-Caribbean Food Store Ltd | Wholesale & retail | 2026 |
| Bexcon Limited | Hospitality | 2002 |
| Beyond Blonde Property Limited | Real estate | 2026 |
| Beyond Your Beliefs Consulting Ltd | Administrative & support | 2023 |
| BG Events Limited | Wholesale & retail | 2014 |
| BG Home Rentals Ltd | Construction | 2021 |
| BGP Consulting Limited | Professional & scientific | 2014 |
| BH Fitness Ltd | Arts & recreation | 2023 |
| BH Safety Services Limited | Real estate | 2022 |
| Bhanu Pratap Singh Logistics Limited | Transport & logistics | 2025 |
| Bhanu Singh Logistics Ltd | Transport & logistics | 2025 |
| BHE Homes Limited | Real estate | 2014 |
| Bibbble Ltd | Manufacturing | 2022 |
| Bicester Boiler Services Ltd | Construction | 2010 |
| Big Fellas (BD9) Ltd | Hospitality | 2020 |
| Big Hero Digital Ltd | Information & communication | 2023 |
| Bigfellas Operations Ltd | Administrative & support | 2023 |
| Bijou Betty Limited | Manufacturing | 2018 |
| Billingham Property Services Limited | Real estate | 2025 |
| Billinginvest Inc Limited | Real estate | 2005 |
| Billions Europe Ltd | Manufacturing | 2014 |
| Bilton Transportation Ltd | Other services | 2018 |
| BIM Department Ltd | Information & communication | 2010 |
| Bimscan Limited | Information & communication | 2026 |
| Bioconstruct Newenergy Ltd. | Professional & scientific | 2014 |
| Bioconstruct UK Limited | Professional & scientific | 2017 |
| Bioconsult Ltd | Construction | 2023 |
| Biocontractors Ltd | Manufacturing | 2024 |
| Biome Software Ltd | Information & communication | 2023 |
| Birch Hill Limited | Agriculture & fishing | 2019 |
| Bird & Porter Accounting Limited | Professional & scientific | 2011 |
| Bird Homes Limited | Construction | 2007 |
| Birnie Document Control Solutions Ltd | Administrative & support | 2025 |
| Bisou Ltd | Hospitality | 2025 |
| Bite Worx Ltd | Administrative & support | 2025 |
| Bitforge Services Limited | Information & communication | 2025 |
| Bitpath Ltd | Administrative & support | 2024 |
| Bits of Plastic Ltd | Wholesale & retail | 2022 |
| Bitsbuilders Ltd | Education | 2025 |
| Bitwisedog Limited | Professional & scientific | 2000 |
| BIZ Rates UK Ltd | Professional & scientific | 2020 |
| Bizi Arts Studios CIC | Arts & recreation | 2020 |
| Bizmax Tech Ltd | Information & communication | 2023 |
| BJ Fabrics Ltd | Other services | 2021 |
| BJ Waites Ltd | Professional & scientific | 2023 |
| Bjfm Holdings Limited | Professional & scientific | 2011 |
| Bjfm Limited | Financial services | 2002 |
| BJH Renewables Limited | Professional & scientific | 2021 |
| BJM Aylesbury Ltd | Professional & scientific | 2026 |
| BJM Cage Limited | Administrative & support | 2025 |
| BJM Contracting Ltd | Information & communication | 2026 |
| BJM Evoke Limited | Administrative & support | 2025 |
| BJM Labour Limited | Information & communication | 2026 |
| BJM Payment Solutions Ltd | Professional & scientific | 2024 |
| BJM Samson Security Ltd | Professional & scientific | 2025 |
| BJM Technical Limited | Information & communication | 2023 |
| BJM Umbrella Limited | Professional & scientific | 2025 |
| BJM Workers Ltd | Administrative & support | 2025 |
| BJP Trading Ltd | Construction | 2024 |
| BL Distribution Ltd | Wholesale & retail | 2018 |
| BL Windows Installations and Repairs Ltd | Construction | 2024 |
| Black Cat Professional Services Ltd | Professional & scientific | 2020 |
| Black Diamond Protection Limited | Administrative & support | 2025 |
| Black Lace (NE) Ltd | Other services | 2023 |
| Black Lace Ltd | Other services | 2016 |
| Black Lion Hotel Richmond Limited | Hospitality | 2020 |
| Black Market Stockton Limited | Hospitality | 2014 |
| Black on Silver Limited | Extraterritorial | 2017 |
| Blackbox IP Company Ltd | Professional & scientific | 2020 |
| Blackburn Damp Proofing Limited | Construction | 2015 |
| Blackburn Delivery Ltd | Transport & logistics | 2026 |
| Blackburn Homes Ltd | Construction | 2002 |
| Blackburn Property Rentals Limited | Real estate | 2020 |
| Blackburns (UK) Limited | Wholesale & retail | 2011 |
| Blackstone Safety Group Ltd | Professional & scientific | 2026 |
| Blackwell Civils NE Ltd | Construction | 2025 |
| Blackwell Construction NE Ltd | Construction | 2023 |
| Blackwell Group NE Ltd | Financial services | 2025 |
| Blackwell Plant NE Ltd | Administrative & support | 2025 |
| Blackwell Renewables NE Ltd | Construction | 2025 |
| Blackwells (Butchers) Limited | Wholesale & retail | 1954 |
| Blackwells Street Deli Limited | Hospitality | 2014 |
| Blade Project and Planning Services Ltd | Professional & scientific | 2017 |