| BHD Consultants Ltd | Professional & scientific | 2022 |
| Bhola Homes Ltd | Financial services | 2024 |
| Bhtf Holdings Ltd | Hospitality | 2025 |
| BIA MT Ltd | Transport & logistics | 2021 |
| Bias Accountants Ltd | Professional & scientific | 2015 |
| Bibby Trading Limited | Other services | 2021 |
| Bicknacre Preschool Limited | Health & social care | 2026 |
| Bicoja Ltd | Arts & recreation | 2022 |
| Bidco MTR Ltd | Wholesale & retail | 2026 |
| Bidex Solutions Ltd | Professional & scientific | 2016 |
| Bidston Management Services Limited | Construction | 2012 |
| Biema-British Indian Emergency Medicine Association | Health & social care | 2019 |
| Bifrons Properties Ltd | Real estate | 2022 |
| Big Bamboo Traders Ltd | Wholesale & retail | 2012 |
| Big Business Events Holding Limited | Real estate | 2019 |
| Big Business Events Ltd | Professional & scientific | 2016 |
| Big Foot Brace Ltd | Wholesale & retail | 2025 |
| Big Image Flooring Ltd | Construction | 2019 |
| Big Motors 1 Ltd | Wholesale & retail | 2025 |
| Big Smile Collective C.I.C. | Arts & recreation | 2025 |
| Big Sounds and LOW Skirts Ltd | Wholesale & retail | 2025 |
| Bigger Pear Limited | Hospitality | 2006 |
| Bigger Picture Outcomes Ltd | Information & communication | 2013 |
| Bigger Picture Outcomes Properties Limited | Real estate | 2021 |
| Bigger Picture Outcomes Training Ltd | Administrative & support | 2023 |
| Bigland Builders Limited | Construction | 2005 |
| Bigland Plastering Company Ltd | Construction | 2014 |
| Bilbradsi Brands Ltd | Wholesale & retail | 2002 |
| Bill & Sons Ltd | Other services | 2020 |
| Billam Limited | Professional & scientific | 2024 |
| Billericay Beauty House Ltd | Other services | 2023 |
| Billericay Fertiliser Services Limited | Manufacturing | 2009 |
| Billericay Fertiliser Storage Limited | Manufacturing | 2019 |
| Billericay Fuel Services Limited | Wholesale & retail | 2009 |
| Billericay Heating Limited | Construction | 2007 |
| Billings Fire Protection Limited | Construction | 2025 |
| Bilrose Property Ltd | Real estate | 2023 |
| Bilt Hamber Laboratories Ltd | Manufacturing | 2007 |
| Biltons Limited | Construction | 2011 |
| BIM Resolutions Ltd | Professional & scientific | 2023 |
| Bimfem Beauty Hub Ltd | Wholesale & retail | 2024 |
| Bimsans Designs Services Ltd | Wholesale & retail | 2021 |
| Bimtech Limited | Professional & scientific | 2020 |
| Binder Loams Limited | Construction | 2011 |
| Bindhu & Martin Property Ltd | Real estate | 2025 |
| Binenow Limited | Administrative & support | 2018 |
| Bingo Bass Records Limited | Manufacturing | 2018 |
| Bioscout UK Ltd | Professional & scientific | 2025 |
| Biosense Medical Supplies Limited | Health & social care | 2021 |
| Birak Properties Limited | Real estate | 2009 |
| Birch Building & Decorating Services Ltd | Construction | 2025 |
| Birchwood Holdings (Maldon) Ltd | Professional & scientific | 2023 |
| Birchwood Properties (Essex) Limited | Real estate | 2020 |
| Birchwood Real Estate Limited | Real estate | 2013 |
| Bird Luckin Limited | Other services | 1989 |
| Birds Hollow Productions Ltd | Arts & recreation | 2022 |
| Biriyani BOY Limited | Hospitality | 2019 |
| Birketts Nominees Limited | Professional & scientific | 1987 |
| Birketts Trustees Limited | Administrative & support | 2007 |
| Birketts Trustees Two Limited | Administrative & support | 2017 |
| Birtel Limited | Transport & logistics | 2025 |
| BIS UK Transport Ltd | Transport & logistics | 2019 |
| Bishops Square Services Ltd | Professional & scientific | 2023 |
| Bismark Logistics & Distribution Limited | Transport & logistics | 2025 |
| Bismark Logistics Limited | Transport & logistics | 2020 |
| Bitnappers Ltd. | Information & communication | 2011 |
| Biton Limited | Information & communication | 1982 |
| Biton System Consultants Limited | Information & communication | 1998 |
| Bits and Bytez Ltd | Information & communication | 2023 |
| Bivbrin Design Ltd | Construction | 2014 |
| Bizim Holding | Real estate | 2025 |
| Bizphit LLP | | 2012 |
| Bizsoft Solutions Ltd | Information & communication | 2020 |
| BJL Cleaning Services Ltd | Administrative & support | 2026 |
| BJM Ground Solutions Ltd | Construction | 2025 |
| BL Sound & Light Ltd | Administrative & support | 2018 |
| Black & AYA Ltd | Wholesale & retail | 2022 |
| Black & White Stone Limited | Real estate | 2025 |
| Black Barn Beverages Ltd | Manufacturing | 2026 |
| Black Brook Media Limited | Information & communication | 2016 |
| Black Bull Chelmsford Ltd | Hospitality | 2026 |
| Black Bull Concert Bars Ltd | Hospitality | 2012 |
| Black Bull Outdoor Events Limited | Hospitality | 2010 |
| Black in Black Limited | Wholesale & retail | 2024 |
| Black Label Technology Ltd | Information & communication | 2019 |
| Black Marble Group Ltd | Financial services | 2023 |
| Black Marble Real Estate Ltd | Real estate | 2022 |
| Black Panther Construction Limited | Other services | 2019 |
| Black Panther Facilities Management Ltd | Real estate | 2021 |
| Black Seed Films Limited | Extraterritorial | 2018 |
| Blackalam Ltd | Information & communication | 2025 |
| Blackall Property Ltd | Real estate | 2025 |
| Blackbeard Books Limited | Transport & logistics | 2002 |
| Blackhorn Global Ltd | Information & communication | 2019 |
| Blackilt Limited | Information & communication | 2014 |
| Blackleaf Roofing Limited | Construction | 2022 |
| Blackleys Farm Ltd | Construction | 2022 |
| Blackmore Mckenzie Limited | Professional & scientific | 2025 |
| Blackrock Construction Supplies Limited | Wholesale & retail | 2017 |
| Blackrock Property & Estates Limited | Real estate | 2022 |