| Billericay Building (Essex) Ltd | Construction | 2018 |
| Billericay Cctv and Alarms Ltd | Construction | 2019 |
| Billericay Driveways Limited | Administrative & support | 2025 |
| Billericay Fireplaces Limited | Manufacturing | 2012 |
| Billericay Home Extensions Ltd | Construction | 2022 |
| Billericay Scaffolding Limited | Construction | 2013 |
| Billet Customs Limited | Information & communication | 2024 |
| Billions and Bullions Ltd | Extraterritorial | 2024 |
| Bills Carpets Limited | Construction | 2025 |
| Billys Painters Ltd | Construction | 2025 |
| Biltong Direct Ltd | Manufacturing | 2025 |
| BIM Factory Limited | Administrative & support | 2014 |
| Bimah & Co Ltd | Wholesale & retail | 2025 |
| Bimvic Limited | Other services | 2014 |
| Binnach Education & Publishing Ltd | Information & communication | 2019 |
| Biochem Analytics Ltd | Administrative & support | 2013 |
| Bionex Energy Savings Ltd | Energy | 2025 |
| Biplan Limited | Health & social care | 2010 |
| Birch Sign Services Ltd | Construction | 2013 |
| Bird and Hound Limited | Extraterritorial | 2026 |
| Birtok Transport Ltd | Transport & logistics | 2019 |
| Bishopthorpe Services Ltd | Professional & scientific | 2020 |
| Bisma Hussain Ltd | Wholesale & retail | 2024 |
| Bison Roofing Portsmouth Limited | Construction | 2025 |
| Bison Security Posts & Bollards Limited | Professional & scientific | 2014 |
| Bistritz Property Management Ltd | Real estate | 2019 |
| Bitris Transport Ltd | Transport & logistics | 2025 |
| BIW Design Ltd | Administrative & support | 2018 |
| Bizan Construction Ltd | Construction | 2014 |
| BIZAU777CONSTRUCTION Limited | Construction | 2022 |
| Biztactics Limited | Wholesale & retail | 2023 |
| BJ Ventures Limited | Construction | 2014 |
| BJE Enterprises Ltd | Wholesale & retail | 2018 |
| Black Horse Realty Limited | Real estate | 2009 |
| Black Line Coffee Limited | Manufacturing | 2026 |
| Black Seven Casa Ltd | Real estate | 2022 |
| Black Tories Ltd | Other services | 2023 |
| Blackbird Sound Limited | Information & communication | 2017 |
| Blackcache Labs Ltd | Wholesale & retail | 2026 |
| Blackline Commerce Limited | Professional & scientific | 2026 |
| Blackstar Live Limited | Arts & recreation | 2011 |
| Blackstar Shipping Limited | Transport & logistics | 2005 |
| Blackthorn Plant Hire Limited | Other services | 2021 |
| Blackwater Kitchens Limited | Other services | 2020 |
| Blackwater Racking Solutions Ltd | Construction | 2022 |
| Blades (Holdings) Limited | | 1989 |
| Blanc Dental Hygiene Suite Ltd | Health & social care | 2021 |
| Blast, Spray & Polish Ltd | Other services | 2008 |
| Blaze HR Limited | Information & communication | 2025 |
| BLB Property Management Ltd | Real estate | 2022 |
| BLC LAB Ltd | Wholesale & retail | 2024 |
| Blem Group Limited | Real estate | 2023 |
| Blenheim Steel Limited | Construction | 2021 |
| Blescorp Limited | Health & social care | 2010 |
| BLH Group Limited | Construction | 2012 |
| Bling Wheels Limited | Manufacturing | 2013 |
| Bliss Oasis Limited | Health & social care | 2024 |
| Blkiam Ltd | Manufacturing | 2023 |
| BLN Joinery Ltd | Construction | 2019 |
| Block Maintenance Ltd | Construction | 2020 |
| Blossoming Believers Ltd | Education | 2024 |
| BLS84 Consulting Ltd | Financial services | 2023 |
| Blue 8 GAS Services Ltd | Construction | 2024 |
| Blue Circle Express Ltd | Transport & logistics | 2016 |
| Blue Construction Group Ltd | Construction | 2025 |
| Blue Diamond Event Management Ltd | Administrative & support | 2024 |
| Blue Infinity Developments Limited | Real estate | 2019 |
| Blue Light Mentality Limited | Wholesale & retail | 2022 |
| Blue Line Cleaning Limited | Wholesale & retail | 2020 |
| Blue Motor Finance DD 2 Limited | Financial services | 2019 |
| Blue Motor Finance DD Limited | Professional & scientific | 2014 |
| Blue Mountain Intelligence Ltd | Construction | 2024 |
| Blue Peak Cleaning Solutions Ltd | Administrative & support | 2025 |
| Blue Pear Cleaning Limited | Administrative & support | 2020 |
| Blue Planet BIO Renewables Ltd | Professional & scientific | 2026 |
| Blue Plastic Limited | Administrative & support | 2010 |
| Blue Utility Ltd | Construction | 2019 |
| Blue-Dwell Limited | Real estate | 2002 |
| Bluebell of London Limited | Wholesale & retail | 2022 |
| Blueboard Supported Living UK Ltd | Administrative & support | 2022 |
| Bluefin Sushi Ltd | Wholesale & retail | 2025 |
| Bluehill Property Ltd | Real estate | 2022 |
| BLUEMOONSHOP21 Ltd | Wholesale & retail | 2022 |
| Bluevangas Ltd | Information & communication | 2023 |
| Bluevapour Limited | Other services | 2016 |
| Bluewater Lakes France Ltd | Agriculture & fishing | 2024 |
| Blume Holdings Limited | Health & social care | 2019 |
| Blumotion Engineering Limited | Professional & scientific | 2016 |
| Blupace Digital Limited | Information & communication | 2025 |
| Blush Brentwood Ltd | Other services | 2021 |
| BM Carpentry&Joinery Ltd | Construction | 2018 |
| BM Projects Building Services Ltd | Construction | 2021 |
| BM Projects Ltd | Construction | 2015 |
| BMA Electrical Limited | Construction | 2015 |
| BMA Real Estate Limited | Real estate | 2018 |
| BMA UK Investments Ltd | Real estate | 2021 |
| BMB Steel Structures Limited | Manufacturing | 2017 |
| BMC &Sons Limited | Construction | 2022 |
| Bmcm Services Ltd | Construction | 2014 |
| BME Wellness Ltd | Other services | 2021 |