| Book Property Concierge Ltd | Administrative & support | 2022 |
| Book Property Services Ltd | Construction | 2019 |
| Book Your Transfer Limited | Administrative & support | 2019 |
| Boombod Ltd | Wholesale & retail | 2013 |
| Booth Precision Engineering Ltd | Construction | 2019 |
| Bothy Consulting Limited | Professional & scientific | 2024 |
| Bottlejob Limited | Wholesale & retail | 2019 |
| Boulden Holdings Limited | Financial services | 2017 |
| Boulud Commercial Limited | Real estate | 2022 |
| Boulud Holdings Limited | Professional & scientific | 2016 |
| Boulud Residential 1 Limited | Real estate | 2018 |
| Boulud Residential Limited | Real estate | 2017 |
| BOW Common Lane Management Limited | Households | 1998 |
| BOW Village Holdings Limited | Financial services | 2023 |
| BOW Village Limited | Real estate | 2003 |
| Bow-Diva Ltd | Wholesale & retail | 2024 |
| Bowyer Bryce (Surveyors) Limited | Real estate | 1979 |
| Bowyer Bryce LLP | | 2019 |
| Boxora Ltd | Real estate | 2025 |
| BP Agencies Limited | Financial services | 2023 |
| BP London Construction Limited | Construction | 2021 |
| BPH Property Holdings Ltd | Real estate | 2026 |
| BQ Soluctions Ltd | Other services | 2021 |
| BR Pharma International Limited | Wholesale & retail | 1998 |
| Brace Face Ltd | Health & social care | 2023 |
| Brackenbury Road Investment Co.Limited | Real estate | 1959 |
| Bracket Films LLP | | 2013 |
| Bradon Ltd | Real estate | 2021 |
| Brady’S Building Services Limited | Construction | 2026 |
| Braeside Infants School Limited | Extraterritorial | 2025 |
| Braeside Junior School Limited | Extraterritorial | 2025 |
| Braeside Nursery School Limited | Extraterritorial | 2025 |
| Braeside Prep School Limited | Education | 2025 |
| Braeside Preparatory School Limited | Extraterritorial | 2025 |
| Braeside Primary School Limited | Extraterritorial | 2025 |
| Braeside School Limited | Education | 1963 |
| Branded Properties Limited | Administrative & support | 2015 |
| Brandphoenix Holdings Limited | Wholesale & retail | 2023 |
| Branson Leisure Limited | Manufacturing | 2006 |
| Brant House RTM Company Ltd | Households | 2018 |
| Brave Group Europe Limited | Wholesale & retail | 2023 |
| Bravo Building Services Limited | Construction | 2001 |
| Bravo Criteria Limited | Information & communication | 2006 |
| Braydon Capital Limited | Real estate | 2025 |
| Braydon Capital SUB Limited | Real estate | 2025 |
| Braydon Homes Limited | Real estate | 2021 |
| Braydon Properties Limited | Real estate | 2021 |
| Braydon Trading Limited | Wholesale & retail | 2021 |
| Breezy Chat Ltd | Information & communication | 2025 |
| Brendale Enterprises Limited | Other services | 2019 |
| Brendan Hand Limited | Construction | 2012 |
| Brenland Estates LLP | | 2020 |
| Brenland Properties Limited | Real estate | 2013 |
| Brentwood Developments Limited | Construction | 2016 |
| Brickhouse Property Investments Ltd | Real estate | 2015 |
| Brico Holdings Limited | Financial services | 2026 |
| Bridge & Birch Ltd | Manufacturing | 2025 |
| Bridge House Loughton Limited | Households | 2022 |
| Bridge House Mews Management Company Limited | Households | 2022 |
| Bridgepoint Builders Network Ltd | Administrative & support | 2025 |
| Briegan Estates Ltd | Households | 2025 |
| Bright Futures Day Nursery Highams Green Limited | Education | 2012 |
| Bright Learners Ltd | Education | 2009 |
| Bright Sage Limited | Real estate | 2025 |
| Bright Start Limited | Real estate | 2022 |
| Bright Steel Fabrication Ltd | Manufacturing | 2025 |
| Brightland Estates Limited Partnership | | 2006 |
| Brightline Electrical Group Ltd | Construction | 2023 |
| Brightside Limited | Real estate | 1992 |
| Brilliant Structure Ltd | Mining & quarrying | 2024 |
| Brinkworth Fisher Property Services Limited | Real estate | 2019 |
| Bristol Soft Furnishing Ltd | Other services | 2025 |
| Britbulgar Journeys Ltd | Transport & logistics | 2024 |
| Brits Connect Ltd | Hospitality | 2015 |
| Broad International Limited | Wholesale & retail | 2001 |
| Broadway Real Estate LLP | | 2013 |
| Brodie Court RTM Company Limited | Households | 2008 |
| Broe Hold Co Ltd | Financial services | 2023 |
| Brome and Schimmer Limited | Wholesale & retail | 1993 |
| Bronx Boxing Ltd | Education | 2019 |
| Brook Avenue Property Ltd | Real estate | 2023 |
| Brook Farm Equestrian Limited | Arts & recreation | 2012 |
| Brook Street Real Estates Ltd | Real estate | 2025 |
| Brookemead Associates Limited | Information & communication | 2002 |
| Brookheath Limited | Construction | 2003 |
| Brooks Laundry LLP | | 2017 |
| Browline Services Ltd | Information & communication | 2019 |
| Brown Box Paper Co Ltd | Professional & scientific | 2000 |
| Brown Property Holdings UK Ltd | Real estate | 2021 |
| Browns Domestic & Commercial Plumbing Ltd | Manufacturing | 2019 |
| Brownz Corporation Ltd | Wholesale & retail | 2025 |
| Brylcleen Ltd | Administrative & support | 2014 |
| Brynport Limited | Administrative & support | 2007 |
| Bsdc Limited | Professional & scientific | 2007 |
| BSL Realisations (2013) Limited | Construction | 2009 |
| Bsmn Consultants Ltd | Information & communication | 2025 |
| BTK Holdings Limited | Health & social care | 2017 |
| BU Utility Ltd | Construction | 2025 |
| Bubbilove Ltd | Wholesale & retail | 2025 |
| Bubbln Limited | Hospitality | 2023 |