| Braxso Ltd | Professional & scientific | 2016 |
| Braywalk Developments Limited | Real estate | 2000 |
| BRC Mart Ltd | Wholesale & retail | 2021 |
| Breaking Bars Ltd | Wholesale & retail | 2025 |
| Breeze XP Couriers Limited | Administrative & support | 2023 |
| Brick & Mortar (Residential) Ltd | Real estate | 2025 |
| Brick & Mortar Doctors Ltd | Construction | 2021 |
| Brick & Mortar Group Holdings Ltd | Real estate | 2025 |
| Brickzila Remodeling Ltd | Construction | 2023 |
| Bridge Facilities Services Ltd | Administrative & support | 2022 |
| Bridgetonn Capital Ltd | Financial services | 2018 |
| Bridgewater Equities Ltd | Real estate | 2024 |
| Bright Delivery Limited | Transport & logistics | 2021 |
| Bright Developments and Investments Ltd | Real estate | 2022 |
| Bright Fabrication Ltd | Manufacturing | 2022 |
| Bright Light & Son's Ltd | Construction | 2024 |
| Bright Progress Limited | Wholesale & retail | 2022 |
| Bright Safety Ltd | Professional & scientific | 2020 |
| Bright Sparkles Ltd | Professional & scientific | 2018 |
| Brightcosmo Limited | Wholesale & retail | 2024 |
| Brightex Limited | Wholesale & retail | 1989 |
| Brighton Retail Investments Ltd | Real estate | 2024 |
| Brightwell Accountants Limited | Professional & scientific | 2019 |
| Brij Global Ltd | Wholesale & retail | 2025 |
| Brilliant Design & Build Ltd | Construction | 2025 |
| Brilliant Payroll Services Ltd | Professional & scientific | 2021 |
| Brilliant Traders Ltd | Wholesale & retail | 2016 |
| Bristol Pill Limited | Real estate | 2025 |
| Brit Media 360 Limited | Information & communication | 2017 |
| Brit Property Ltd | Construction | 2019 |
| Britannia Sterling Recruitment Limited | Administrative & support | 2026 |
| British and Commonwealth Stamp Company Limited | Wholesale & retail | 2007 |
| Britohomes Limited | Real estate | 2025 |
| Broadwalk Homes Limited | Real estate | 2023 |
| Broadway Town 1 Limited | Real estate | 2023 |
| Broadway Town Ltd | Real estate | 2016 |
| Brockley Convenience Limited | Wholesale & retail | 2018 |
| Brombo WBM Limited | Health & social care | 2021 |
| Bronfman Schuster Limited | Wholesale & retail | 2016 |
| Bronson Services Limited | Information & communication | 2025 |
| Bronze Property Maintenance Ltd | Construction | 2026 |
| Brookbond Bilisim Danismanlik Limited | Other services | 2018 |
| Brookstone Property Group Ltd | Real estate | 2025 |
| Broom & Beyond Cleaning Company Ltd | Administrative & support | 2025 |
| Brother Singh's Ltd | Wholesale & retail | 2023 |
| Brothers & Co Ltd | Wholesale & retail | 2012 |
| Brothers Group Investment Limited | Administrative & support | 2017 |
| Brown & Burk UK Limited | Manufacturing | 2000 |
| Brown Aura Ltd | Wholesale & retail | 2026 |
| Brown Bear Bushcraft Ltd | Agriculture & fishing | 2023 |
| Brown Flame Ltd | Wholesale & retail | 2026 |
| Browski Print Shop Ltd | Manufacturing | 2025 |
| BRT General Trading Ltd | Wholesale & retail | 2026 |
| Brytex Limited | Wholesale & retail | 2025 |
| BS Food & Wine Ltd | Wholesale & retail | 2025 |
| BS Global Stores Ltd | Wholesale & retail | 2018 |
| BSA Builders Limited | Construction | 2007 |
| BSA Tuition Services Ltd | Education | 2013 |
| BSC Construction Ltd | Construction | 2019 |
| BSC Gadgets Ltd | Wholesale & retail | 2021 |
| BSC Letting Ltd | Real estate | 2019 |
| Bshpropertiesuk Limited | Real estate | 2025 |
| BSK Courier and Cargo Limited | Transport & logistics | 2025 |
| BSK Technologies Ltd | Information & communication | 2017 |
| BSM Traders Ltd | Wholesale & retail | 2018 |
| BSN Enterprises Ltd | Wholesale & retail | 2024 |
| BSP 1948 Limited | Administrative & support | 2025 |
| BSR Reading Ltd | Real estate | 2021 |
| BSV Project Consulting Limited | Information & communication | 2014 |
| BTS Capital Limited | Real estate | 2023 |
| BTS International Limited | Wholesale & retail | 2025 |
| Bubbles Bully Films Ltd | Information & communication | 2022 |
| Buckinghamshire Golf Company Limited | Arts & recreation | 1989 |
| Buckinghamshire Park Resort (Holdings) Limited | Hospitality | 2016 |
| Buddha Convenience Store PVT Ltd | Wholesale & retail | 2017 |
| Buddha International Trustees Limited | Financial services | 2021 |
| Budget Transport Ltd | Transport & logistics | 2018 |
| Budgeted Man&Van Ltd | Transport & logistics | 2024 |
| Budi - Building Limited | Construction | 2015 |
| Build & Shine Limited | Construction | 2014 |
| Build Forward Construction Ltd | Construction | 2021 |
| Build Smartly Ltd | Construction | 2018 |
| Build SOM Ltd | Construction | 2025 |
| BUILD2PLAN Construction Ltd | Construction | 2020 |
| BUILD4BEST Builders Ltd | Construction | 2025 |
| Buildent Ltd | Construction | 2018 |
| Buildentia Group Limited | Construction | 2026 |
| Builders of Light Limited | Construction | 2025 |
| Buildhive Ltd | Wholesale & retail | 2025 |
| Building Crew Ltd | Construction | 2015 |
| Buildixi Limited | Construction | 2026 |
| Buildsafe Scaffolding Ltd | Construction | 2022 |
| Bukka Consulting Limited | Professional & scientific | 2025 |
| Bulk Enterprise Holdings NW Ltd | Wholesale & retail | 2020 |
| Bulk Paws Ltd | Manufacturing | 2025 |
| Bulk Traders Ltd | Wholesale & retail | 2025 |
| Bull Horns Logistics Ltd | Transport & logistics | 2025 |
| Bulla Construction Limited | Construction | 2025 |
| Bulstrode Investment Limited | Real estate | 2022 |
| Bulstrode London Limited | Real estate | 2013 |