| Beast Golf Ltd | Wholesale & retail | 2022 |
| Beauty and Aesthetics by Karina Ltd | Other services | 2023 |
| BEE Medic Limited | Extraterritorial | 2022 |
| BEE Smith Ltd | Construction | 2012 |
| BEE Systems Limited | Manufacturing | 2021 |
| Beefy Stone Limited | Hospitality | 2022 |
| Bel-Ingle Limited | Construction | 2002 |
| Bell Sands Administration Limited | Households | 2015 |
| Bell Tyre Centre Limited | Wholesale & retail | 2003 |
| Belloria Jewellers Ltd | Wholesale & retail | 2025 |
| Belton Systems Limited | Information & communication | 2004 |
| BEN Davison Properties Limited | Real estate | 2020 |
| BEN Davison Sports Limited | Arts & recreation | 2018 |
| BEN Shan Limited | Professional & scientific | 2011 |
| Benfleet Medical Services Ltd | Health & social care | 2013 |
| Benfleet Motorboat and Yacht Club Limited | Hospitality | 2002 |
| Benson Sedgwick Engineering Limited and Associated Companies Pension Scheme Ltd | Other services | 2022 |
| Benton Design Consultancy Limited | Professional & scientific | 2011 |
| Benu Development Limited | Construction | 2013 |
| Bergs Timber (UK) Limited | Extraterritorial | 2023 |
| Bergs UK Holdings Limited | Financial services | 2005 |
| Berkery Collins Limited | Professional & scientific | 2024 |
| Bespoke Bathrooms Essex Ltd | Construction | 2024 |
| Bespoke Resin Surfaces Ltd | Administrative & support | 2005 |
| Bespoke Risk Solutions Ltd | Financial services | 2010 |
| Betajet Limited | Other services | 2018 |
| Betterpride Limited | Real estate | 2016 |
| Beulah Management Solutions Ltd | Financial services | 2024 |
| Bhakti Creations Limited | Wholesale & retail | 2024 |
| Big House Yeah Ltd | Real estate | 2021 |
| Bigger Investments Ltd | Real estate | 2024 |
| Bignall Consultancy Services Limited | Professional & scientific | 2025 |
| Bill's Traditional Turkish Barbers Limited | Other services | 2017 |
| Billdor Ltd | Construction | 2015 |
| Billericay Financial Services Limited | Financial services | 2007 |
| Billy Fairley Trading Ltd | Wholesale & retail | 2026 |
| Birchwood Solutions Limited | Information & communication | 2010 |
| Bishops Yard Ltd | Real estate | 2023 |
| Bitus UK Limited | Wholesale & retail | 1990 |
| Bitus Wood Products Limited | Extraterritorial | 2018 |
| Bizenergy Ltd | Professional & scientific | 2024 |
| Black Cat Consultancy Limited | Information & communication | 2001 |
| Blackhawk Corporate Limited | Professional & scientific | 2022 |
| Blackwaterfoot Limited | Real estate | 2023 |
| Blinds Shutters Awnings and Curtains Ltd | Construction | 2020 |
| Blissett Group Holdings Limited | Real estate | 2024 |
| Bloomwood Photography Limited | Professional & scientific | 2012 |
| Blown Fuse Ltd | Arts & recreation | 2016 |
| BLU Property Ltd | Real estate | 2021 |
| BLUE30 Ltd | Administrative & support | 2021 |
| BLW Insurance Brokers Ltd | Financial services | 1971 |
| Bmvn Ltd | Professional & scientific | 2015 |
| Boardroom Coaching Limited | Professional & scientific | 2025 |
| Boatco UK Ltd | Manufacturing | 2014 |
| Boatsuk Limited | Extraterritorial | 2014 |
| Bodymotion Limited | Health & social care | 2021 |
| Bodysync AI Ltd | Health & social care | 2025 |
| Bonsi Limited | Hospitality | 2007 |
| Bonville Ltd | Wholesale & retail | 2011 |
| Bookalicious Limited | Wholesale & retail | 2018 |
| Booksbymetre Limited | Manufacturing | 2014 |
| Boscombe Joinery & Mouldings Limited | Manufacturing | 2010 |
| Boss Drainfix Limited | Construction | 2020 |
| Boss Groundwork Group Limited | Construction | 2018 |
| Bosy Contracts Limited | Construction | 2011 |
| Bouxe Steelworks Limited | Construction | 2017 |
| Box Park Storage Limited | Transport & logistics | 2021 |
| Brad Simpson’S Hire Ltd | Hospitality | 2023 |
| BRC Design and Build Ltd | Construction | 2017 |
| Breakpoint Padel Limited | Arts & recreation | 2025 |
| Breakthrough Plant & Equipment Limited | Administrative & support | 2020 |
| Breeden Heating and Plumbing Ltd | Construction | 2014 |
| Brentwood Films Limited | Information & communication | 2014 |
| Brett Osborn Electrical Limited | Construction | 2014 |
| Brett's Properties Limited | Other services | 2014 |
| Brickhouse Homes Ltd | Real estate | 2019 |
| Bricks and Pieces Ltd | Wholesale & retail | 2025 |
| Bridge Street Residents Association Limited | Households | 2012 |
| Brien Joinery Limited | Construction | 2003 |
| Bright Programming Limited | Information & communication | 2015 |
| Bright PV Solutions Limited | Professional & scientific | 2018 |
| Brightcoast Limited | Other services | 2017 |
| Britannia Bespoke Furniture Ltd | Manufacturing | 2018 |
| Broadways Maharani Limited | Hospitality | 2024 |
| Brooklyn Interiors Limited | Professional & scientific | 2018 |
| Brosh Limited | Hospitality | 2007 |
| Browns Professional Ventilation Maintenance Limited | Administrative & support | 2023 |
| Brows by Heidi Ltd | Other services | 2022 |
| Brunel Management (Clacton) Limited | Administrative & support | 2008 |
| Building Blocks Care Limited | Health & social care | 2024 |
| Building Blocks Reablement Limited | Health & social care | 2024 |
| Buildsmart Construction Limited | Construction | 2021 |
| Bulldog Interiors Ltd | Construction | 2014 |
| Burgess Haulage Limited | Transport & logistics | 2014 |
| Business AI Studio Limited | Professional & scientific | 2023 |
| BXT Wealth Ltd | Professional & scientific | 2023 |
| Byford Properties Limited | Real estate | 2002 |
| Byfords Food Hall Limited | Wholesale & retail | 2000 |
| Byfords Properties Ltd | Real estate | 2023 |
| Byolojet Limited | Professional & scientific | 2019 |