| Bezalel Solutions Ltd | Health & social care | 2025 |
| BG Testing Consultancy Services Limited | Professional & scientific | 2017 |
| BGN Transport Ltd | Administrative & support | 2023 |
| Bh&M Ltd | Information & communication | 2026 |
| Bhardwaj Medical Services Limited | Health & social care | 2019 |
| BI & Joseph Rentals Ltd | Hospitality | 2025 |
| Biam Solutions Ltd | Information & communication | 2023 |
| Bianca Sobell Holdings Limited | Manufacturing | 2021 |
| Big Action Marketing Limited | Professional & scientific | 2025 |
| Big Belly Restaurant Ltd | Hospitality | 2026 |
| Big Chill Group Limited | Financial services | 2005 |
| BIG2026 Ltd | Administrative & support | 2025 |
| Bilash Kent Ltd | Hospitality | 2026 |
| Billings Property Ltd | Construction | 2025 |
| BIN Masters (Kent) Limited | Manufacturing | 2009 |
| BIN Masters Franchising Limited | Professional & scientific | 1999 |
| Bina Solutions Ltd | Health & social care | 2022 |
| Bing Digital Consultancy Ltd | Information & communication | 2014 |
| BIO Harmony Consulting Ltd. | Health & social care | 2022 |
| Bioknicks Ltd | Wholesale & retail | 2009 |
| Biovita Medical Limited | Professional & scientific | 2009 |
| BIP Couriers Limited | Transport & logistics | 2012 |
| Birchwood Construction & Carpentry Limited | Other services | 2017 |
| Birmingham Truck Tyre Ltd | Wholesale & retail | 2013 |
| Bishop Medicals Limited | Public administration | 2023 |
| Bishop Property & Renovations Ltd | Real estate | 2024 |
| BIT Reactor Limited | Information & communication | 2017 |
| Bixeans Ltd | Manufacturing | 2024 |
| BJ Joyous Limited | Health & social care | 2017 |
| BJC Electrical Ltd | Construction | 2016 |
| BK Wills Limited | Professional & scientific | 2017 |
| BKA Engineering Services Ltd | Construction | 2026 |
| BKB Housing Ltd | Real estate | 2024 |
| BKR Construction and Landscaping Limited | Construction | 2016 |
| BL Foods Ltd | Wholesale & retail | 2025 |
| BL Vent Ltd | Construction | 2012 |
| Blace Consultants Ltd | Professional & scientific | 2023 |
| Black and Bold Immigration Services Limited | Professional & scientific | 2025 |
| Black British Parent Ltd | Wholesale & retail | 2022 |
| Black Cat Data Cabling Limited | Information & communication | 2023 |
| Black Cat GRP Limited | Financial services | 2023 |
| Black Cat IT Support Ltd | Administrative & support | 2014 |
| Black Cat PC Services Ltd | Information & communication | 2010 |
| Black Nell Limited | Information & communication | 2003 |
| Black Orchid Properties Limited | Real estate | 2020 |
| Black Trident Holdings Limited | Financial services | 2014 |
| Black Urchin Limited | Hospitality | 2025 |
| Blackbadger Limited | Information & communication | 2008 |
| Blackbear Healthcare Limited | Health & social care | 2021 |
| Blackberry Lane (Ashford) Management Company Limited | Households | 2018 |
| Blacknell Auto UK Ltd | Wholesale & retail | 2025 |
| Blacksmith Health Care Limited | Public administration | 2023 |
| Blacksmith Outreach Limited | Hospitality | 2023 |
| Blackstone Hygienic Solutions Limited | Administrative & support | 2025 |
| Blackthorn Solutions CIC | Health & social care | 2024 |
| Blacktop Design Limited | Construction | 2011 |
| Blagdon Associates Limited | Information & communication | 2008 |
| Blaze Couriers Ltd | Transport & logistics | 2011 |
| BLB Asset and Finance Limited | Real estate | 2021 |
| Blbb Construction Ltd | Construction | 2018 |
| Blends Construction Services Limited | Construction | 2025 |
| Blessed Ighodaro Ltd | Wholesale & retail | 2026 |
| Blessing-Kudzai Ltd | Professional & scientific | 2010 |
| Bliss Staircase Specialists Ltd | Manufacturing | 2026 |
| Bloomfield Independent Ltd | Wholesale & retail | 2023 |
| Bloomin Bronze Tanning Ltd | Other services | 2025 |
| Blossom & Bloom Services Ltd | Administrative & support | 2017 |
| Blossom HER Way Ltd | Other services | 2025 |
| Blossom Salon Ltd | Other services | 2023 |
| Blossoming Developments Ltd | Real estate | 2025 |
| Blossoms Prime Facility Solutions Ltd | Administrative & support | 2026 |
| BLP Maintenance Ltd | Energy | 2020 |
| BLQ Consulting Ltd | Information & communication | 2017 |
| BLQ Ventures Ltd | Real estate | 2023 |
| BLU 3 (UK) Limited | Construction | 2004 |
| BLU Silicon Technology Limited | Information & communication | 2015 |
| BLU3 (Holdings) Limited | Financial services | 2005 |
| BLU3 Group Holdings Limited | Financial services | 2025 |
| Blubin Technologies Limited | Information & communication | 2026 |
| Blubird Investments Ltd | Financial services | 2025 |
| Blue Courier Ltd | Transport & logistics | 2016 |
| Blue Lily Wood Ltd | Professional & scientific | 2021 |
| Blue Lotus Collective C.I.C. | Health & social care | 2024 |
| Blue Rain Limited | Hospitality | 2025 |
| Blue Serv Autos Ltd | Wholesale & retail | 2023 |
| Blue Skies School Ltd | Administrative & support | 2007 |
| Blue Sky Accountants Limited | Professional & scientific | 2013 |
| Blue Tulip Wealth Management Limited | Professional & scientific | 2020 |
| Blue Wyvern Limited | Professional & scientific | 2019 |
| Bluebell School of Dance and Performing Arts Ltd | Education | 2026 |
| Bluebells Childcare Services Ltd | Education | 2023 |
| Bluebells Events Ltd | Hospitality | 2024 |
| Bluebells Investment Limited | Professional & scientific | 2012 |
| Bluebellwoods Properties Ltd | Real estate | 2021 |
| Blueberry Property Ventures Limited | Real estate | 2026 |
| Blueprint Illustrated Ltd | Administrative & support | 2016 |
| Bluestone Kent Ltd | Construction | 2023 |
| Bluevelvety Tiny Tots Limited | Health & social care | 2018 |
| BM NDT Inspection Services Ltd | Professional & scientific | 2023 |
| BMC Builders Kent Ltd | Construction | 2015 |