| Baldwin Security Services Limited | Construction | 2025 |
| Balfour Commercial Limited | Real estate | 2015 |
| Ballaro Associates LLP | | 2012 |
| Ballinluska Limited | Real estate | 2015 |
| Ballyjames Limited | Professional & scientific | 2015 |
| Baltimore Wharf UK (GP) Limited | Real estate | 2018 |
| BAM BAM Post Limited | Professional & scientific | 2012 |
| Bamse Services Ltd | Transport & logistics | 2015 |
| Banjo Property London Ltd | Construction | 2020 |
| Banof Services Ltd | Administrative & support | 2021 |
| Barbara Castle Practice Limited | Health & social care | 2007 |
| Barclays Roofing & Building Ltd | Construction | 2023 |
| Barcourt Limited | Professional & scientific | 1992 |
| Baretay Ltd | Hospitality | 2019 |
| Barfields Maintenance Ltd | Construction | 2020 |
| Barfit Joinery Ltd | Manufacturing | 2019 |
| Barley Properties Holdings Limited | Financial services | 2017 |
| Barley Properties Limited | Real estate | 2010 |
| Barnes London Holdings Limited | Financial services | 2024 |
| Barnston Land Limited | Real estate | 2025 |
| Barnwood Property Investments Limited | Real estate | 2024 |
| Barons Court (Ilford) Management Company Limited | Real estate | 1988 |
| Baroque London Ltd | Wholesale & retail | 2019 |
| Barrells Down Road Management Limited | Real estate | 2013 |
| Barrelmans Point Management Company Limited | Real estate | 2023 |
| Barry Turner & SON Limited | Construction | 2005 |
| Barrygozz Limited | Other services | 2025 |
| Bartholomew House (Repton Park) RTM Company Limited | Real estate | 2020 |
| Base Fabrications Limited | Construction | 2008 |
| Basildon Hill Developments Ltd | Real estate | 2023 |
| Baskin Walsh Ltd | Professional & scientific | 2013 |
| Basstion Limited | Construction | 1994 |
| Bath and Tile Superstore Limited | Wholesale & retail | 2018 |
| Bathroom Solutions Group Ltd | Construction | 2019 |
| Battles Bequest Limited | Professional & scientific | 2001 |
| Baybridge Group Ltd | Construction | 2020 |
| Bayside Automotive Ltd | Wholesale & retail | 2023 |
| BB Telecom Ltd | Information & communication | 2015 |
| BCL Fashion Ltd | Wholesale & retail | 2023 |
| BCO Enterprises Partnership LLP | | 2018 |
| BDL (Churchill) Limited | Construction | 2025 |
| BDL (Civic) Limited | Construction | 2024 |
| BDL (Nazeing) Limited | Administrative & support | 2026 |
| BDL CP12 Limited | Administrative & support | 2026 |
| BDS Holdings London Ltd | Financial services | 2024 |
| BE Psychology Ltd | Health & social care | 2022 |
| Beach Level Limited | Professional & scientific | 2021 |
| Beachview Consortium Limited | Administrative & support | 2014 |
| Beachview Corporation Limited | Real estate | 2007 |
| Beachwear Ltd | Wholesale & retail | 2018 |
| Beales Electrical Limited | Construction | 2024 |
| Bear Lane Arches Limited | Construction | 2018 |
| Bear the Palm Ltd | Information & communication | 2024 |
| Beattheheat Limited | Energy | 2007 |
| Beaumont Park Residents Company Limited | Households | 1993 |
| Beautiful Presentations Limited | Other services | 2002 |
| Beauty Spot (London) Ltd | Administrative & support | 2004 |
| Bebe & Ceyiz Sarayi London Ltd | Wholesale & retail | 2025 |
| Becken Hall Builders Ltd | Construction | 2019 |
| BED BUG Detection Services Ltd | Wholesale & retail | 2025 |
| Bedin & Finch Immigration LLP | | 2023 |
| Beech Management (Brook Lodge) Limited | Real estate | 1999 |
| Beech Two Limited | Real estate | 2011 |
| Beechoak Farm Montessori Pre-School Limited | Education | 1996 |
| Beers Claybourne Ltd. | Professional & scientific | 1993 |
| BEIAT2 Limited | Construction | 2025 |
| Bekes Foods Ltd | Hospitality | 2025 |
| Bekes Limited | Hospitality | 2024 |
| Beks Foods Ltd | Hospitality | 2019 |
| Belga Invest Limited | Real estate | 2017 |
| Belgrave Holdings Management Ltd | Financial services | 2026 |
| Belgrave Village Block Management Company Limited | Real estate | 2024 |
| Belgrave Village Management Company Limited | Real estate | 2023 |
| Belgraves of London Ltd | Transport & logistics | 2013 |
| Belgraves Travel Management Limited | Transport & logistics | 2022 |
| Bella Blinds, Shutters & Curtains Limited | Manufacturing | 2025 |
| Bella James Productions Ltd | Information & communication | 2024 |
| Bellanhurst Sprinkler Systems Limited | Construction | 2019 |
| Bellecity Limited | Construction | 2001 |
| Bellron Ltd | Financial services | 2017 |
| Belmont Asset Protection Ltd | Other services | 2025 |
| Belmont Close Investments Limited | Extraterritorial | 2016 |
| Belsize Park Developments Limited | Administrative & support | 2008 |
| Beluga Blade Ltd | Wholesale & retail | 2025 |
| BEN ARI Properties Limited | Financial services | 2026 |
| BEN Pentreath Limited | Professional & scientific | 2004 |
| Benalex Group Ltd | Professional & scientific | 2007 |
| Benavente Trading Ltd | Wholesale & retail | 2023 |
| Bendall Mechanical Services Ltd | Construction | 2025 |
| Benley Estates Ltd | Real estate | 2024 |
| Benning Estates (Services) Limited | Real estate | 2022 |
| Benning Estates Holdings Limited | Financial services | 2022 |
| Bentley Creative Media Ltd. | Information & communication | 2007 |
| Benzo Corp Limited | Hospitality | 2023 |
| Bera Software & Consultancy Ltd | Information & communication | 2019 |
| Beresford & Co Properties Ltd | Real estate | 2026 |
| Berg Partners International Ltd | Professional & scientific | 2016 |
| Berkshire Securities Limited | Construction | 1992 |
| Berry Holdings Limited | Professional & scientific | 2000 |
| Bertan Contractors Ltd | Construction | 2015 |