| Billericay Cleaning & Supplies Ltd | Wholesale & retail | 2023 |
| Billericay Glass Co Limited | Construction | 1986 |
| Billericay MOT Centre Limited | Wholesale & retail | 2016 |
| Billow Track Ltd | Information & communication | 2025 |
| Bimtec Limited | Professional & scientific | 2025 |
| Bindhuse Limited | Health & social care | 2024 |
| BIR Property Rental Limited | Real estate | 2007 |
| Biriyani Ltd | Hospitality | 2022 |
| Birkys Limited | Construction | 2026 |
| Birth Nurture Limited | Health & social care | 2012 |
| Bishahockey Limited | Arts & recreation | 2008 |
| Bizlinks Ltd | Professional & scientific | 2008 |
| Bizneeds Services Ltd | Wholesale & retail | 2026 |
| Bjorswitch Limited | Administrative & support | 2017 |
| BKS Retail Ltd | Wholesale & retail | 2023 |
| Black Badge Chauffeurs Ltd | Transport & logistics | 2023 |
| Black Bull Court RTM Company Limited | Real estate | 2014 |
| Black Pixel Studios Ltd | Professional & scientific | 2024 |
| Black Squirrel Distillery Ltd | Manufacturing | 2019 |
| Blackburn Bailey Group Limited | Manufacturing | 2001 |
| Blacked Capital Limited | Construction | 2018 |
| Blacklin Company Limited | Professional & scientific | 2022 |
| Blackmore Meadow (Stalbridge) Management Company Limited | Households | 2019 |
| Blackthorne Stratton Ltd | Administrative & support | 2026 |
| Blackwood Home Improvements Limited | Construction | 2014 |
| Bladetop Limited | Real estate | 1999 |
| Blake Contractors Limited | Construction | 2001 |
| Blake Court Residents Association Limited | Real estate | 1999 |
| Blake Group Services Limited | Financial services | 2024 |
| Blencare Limited | Real estate | 1991 |
| BLESSED11223 Limited | Health & social care | 2024 |
| Blink Intermediary Solutions Ltd | Financial services | 2011 |
| Blink Security Service Ltd | Administrative & support | 2016 |
| Bliss Electrical Limited | Construction | 2020 |
| Bliss Software Infrastructure Limited | Information & communication | 2026 |
| Blitz&Shine Ltd | Administrative & support | 2025 |
| Block 28 Limited | Real estate | 2024 |
| Block 29 Limited | Real estate | 2024 |
| Block One Investments Limited | Financial services | 2017 |
| Blomfield Mortgage Services Ltd | Financial services | 2023 |
| Bloomfield Properties Limited | Real estate | 2019 |
| Blooms of Thorpe Bay Ltd | Wholesale & retail | 2023 |
| Blossom JJ Empire Limited | Real estate | 2023 |
| Blossom Rose Recruitment Limited | Administrative & support | 2025 |
| Bludfish Developments Limited | Real estate | 2021 |
| Blue Ball 2014 Limited | Real estate | 2014 |
| Blue Barrels Global Limited | Financial services | 2017 |
| Blue Elephant Estates Limited | Real estate | 2022 |
| Blue Nile Foods Ltd | Wholesale & retail | 2020 |
| Blue Root Store Ltd | Wholesale & retail | 2026 |
| Blue Sapphire Mortgages Limited | Financial services | 2024 |
| Bluebell Gardens (Morley) Management Company Limited | Households | 2016 |
| Bluebell Walk (Harrietsham) Management Company Ltd | Households | 2019 |
| Blueline Security Management Ltd | Administrative & support | 2014 |
| Bluevista Accountants Ltd | Professional & scientific | 2023 |
| Bluevista Ltd | Financial services | 2025 |
| Bluewater Construction Limited | Construction | 1997 |
| Bluu Food Co Ltd | Hospitality | 2021 |
| Blyth Roofing Ltd | Construction | 2015 |
| BMI Interiors Ltd | Construction | 2023 |
| BMI Services Ltd | Construction | 2020 |
| Board and Governance Consultancy Limited | Professional & scientific | 2017 |
| Boba & Pearl Ltd | Wholesale & retail | 2021 |
| Bobulate Limited | Professional & scientific | 2026 |
| Bodington Manor (Adel) Management Company Limited | Households | 2014 |
| Boiling Frogs Ltd | Professional & scientific | 2022 |
| Boisson Consultants Limited | Wholesale & retail | 2001 |
| Boldly Beyond Ltd | Wholesale & retail | 2024 |
| Bombay Grilled & Grove Ltd | Hospitality | 2025 |
| Bombora Properties Limited | Real estate | 2022 |
| Bond Stage & Screen Limited | Information & communication | 2024 |
| Bonduk Alliance Limited | Real estate | 2022 |
| Bonduk Syndicate Ltd | Hospitality | 2025 |
| Booklynn Bookkeeping Ltd | Professional & scientific | 2010 |
| Boomerang Digital Media Ltd | Information & communication | 2020 |
| Booo Ltd | Professional & scientific | 2024 |
| Born at the Right Time CIC | Education | 2022 |
| Boscombe Care Homes Limited | Health & social care | 2003 |
| Boss Heating & GAS Ltd | Construction | 2006 |
| Bougie Limited | Wholesale & retail | 2019 |
| Boulevard Lodge Limited | Health & social care | 2011 |
| Bourke Tech Enterprises Ltd | Information & communication | 2024 |
| Bournes Green Chase Limited | Real estate | 2006 |
| Box IT ALL Limited | Administrative & support | 2014 |
| Boxing 101 Limited | Education | 2023 |
| Boxon Ltd | Extraterritorial | 2022 |
| Boxrite Logistics & Packaging Ltd | Transport & logistics | 2025 |
| Brackenwood Management Company Limited | Households | 1984 |
| Bradbaconcg Ltd | Information & communication | 2021 |
| Bradshaw Electrical Ltd | Construction | 2003 |
| Bradworth Properties Limited | Households | 2017 |
| Bramall Commodity Advisors Limited | Professional & scientific | 2017 |
| Brand Consulting Group Limited | Professional & scientific | 2026 |
| Brand IT Guru Limited | Wholesale & retail | 2014 |
| Brand Promotions UK Ltd | Manufacturing | 2010 |
| Brand Property Management Ltd | Real estate | 2021 |
| Brantome Business Services Limited | Professional & scientific | 2013 |
| Braw Enterprises Limited | Information & communication | 2008 |
| Braxted Construction Limited | Construction | 2021 |
| Braxted Properties Ltd | Real estate | 2021 |