| Barely Original Limited | Arts & recreation | 2014 |
| Barfield P a Limited | Manufacturing | 2010 |
| Barker & Hird (PP) Limited | Manufacturing | 1989 |
| Barker & Hird Limited | Extraterritorial | 1989 |
| Barker & Scott Ltd | Professional & scientific | 2026 |
| Barker and Hood (Manchester) Limited | Transport & logistics | 2021 |
| Barker and Hood Limited | Transport & logistics | 2007 |
| Barker Automotive Vehicle Specialist Ltd | Wholesale & retail | 2025 |
| Barker Mortgage Solutions Limited | Professional & scientific | 2023 |
| Barkley Projects (Kelvedon) LLP | | 2012 |
| Barkley Projects Limited Liability Partnership | | 2003 |
| Barkley Projects Properties LLP | | 2008 |
| Barley Meadows Management Company Limited | Households | 1997 |
| Barn OWL Homes Limited | Construction | 2019 |
| Barn Piece Management Company Limited | Professional & scientific | 2015 |
| Barnes Riverside Consulting Limited | Professional & scientific | 2013 |
| Barnhawk Tendring Ltd | Wholesale & retail | 2017 |
| Barningham Creative Electronics Ltd | Extraterritorial | 2012 |
| Baron Alliance Ltd | Information & communication | 2025 |
| Baron Bullions Ltd | Wholesale & retail | 2021 |
| Barons Keep Property Company (London) Limited | Construction | 2009 |
| Baronson Ltd | Administrative & support | 2017 |
| Baros Abyss Ltd | Extraterritorial | 2025 |
| Barr Brickwork Ltd | Administrative & support | 2019 |
| Barretts of Woodbridge Limited | Wholesale & retail | 1969 |
| Barries PH Ltd | Administrative & support | 2017 |
| Barron Property Ltd | Real estate | 2020 |
| Barron's Properties Ltd | Real estate | 2023 |
| Barry Ashmore Consulting Ltd | Professional & scientific | 2020 |
| Bars Logistics Ltd | Transport & logistics | 2020 |
| Bars Security Locksmith Ltd | Other services | 2025 |
| Bartech Control Systems Ltd | Manufacturing | 2023 |
| Bartech Marine Engineering Limited | Extraterritorial | 1998 |
| Bartech Parts Supply Ltd | Professional & scientific | 2019 |
| Bartech Propulsion Limited | Manufacturing | 2021 |
| Bartech Turbos Limited | Professional & scientific | 2013 |
| Bartliff 88 Limited | Administrative & support | 2014 |
| Bartondormer Ltd | Construction | 2021 |
| Bartsons Limited | Construction | 2016 |
| Basca Indian Ltd | Hospitality | 2025 |
| Baseroom Productions Ltd | Information & communication | 2017 |
| Bastidasl Ltd | Information & communication | 2024 |
| Bastion Cyber Security Ltd | Information & communication | 2025 |
| Bastion Financial Planning Limited | Financial services | 2015 |
| Bastow Irwin Recruitment Limited | Administrative & support | 2023 |
| Bastow Irwin Temp Recruitment Ltd | Administrative & support | 2026 |
| Bateman Kildare Ltd | Health & social care | 2010 |
| Bath Blast Ltd | Wholesale & retail | 2025 |
| Bathford Investments 1 Limited Partnership | | 2024 |
| Bathford Investments 2 Limited Partnership | | 2025 |
| Bathford Investments Limited | Financial services | 2024 |
| Bathford Operations Limited | Real estate | 2024 |
| Bathroom Solutions Limited | Administrative & support | 2023 |
| Batt Building Services Ltd | Administrative & support | 2012 |
| Bauble Headz Ltd | Wholesale & retail | 2025 |
| Bavs Homes Ltd | Real estate | 2021 |
| Bawburgh Lakes Ltd | Agriculture & fishing | 2012 |
| Bawley House Management Limited | Real estate | 2015 |
| Baxco Limited | Wholesale & retail | 2009 |
| Baxter Holding Group Limited | Financial services | 2019 |
| Baxter's Property Services Ltd | Construction | 2016 |
| Bay Surveying Ltd | Professional & scientific | 2015 |
| Bayoak Demo Limited | Construction | 2001 |
| Baystart Limited | Wholesale & retail | 1989 |
| Bazzco Ltd | Construction | 2024 |
| BB Business Consultancy Ltd | Real estate | 2023 |
| BB Cabling Ltd | Construction | 2024 |
| BB Colchester and Tendring Ltd | Education | 2025 |
| BB Scaffolding Ltd | Construction | 2023 |
| BBE Wholesale Ltd | Wholesale & retail | 2019 |
| Bblossom Homecare Limited | Health & social care | 2025 |
| BBM (Business) Limited | Manufacturing | 1991 |
| BBT Brickwork Essex Ltd | Construction | 2019 |
| BBT Brickwork London Limited | Construction | 2019 |
| Bc&A Ltd | Hospitality | 2024 |
| BCA Investments Limited | Real estate | 2025 |
| BCG International Services Limited | Manufacturing | 1989 |
| BCM23LOGISTICS Ltd | Transport & logistics | 2015 |
| BCO Electrics Ltd | Construction | 2026 |
| Bcrs Property Limited | Real estate | 2020 |
| BCT Treasury Consultants Limited | Professional & scientific | 2002 |
| BD Frozen Ltd | Wholesale & retail | 2023 |
| Bdbes Limited | Construction | 2014 |
| Bdesha Properties Limited | Real estate | 2020 |
| BDF Building Ltd | Administrative & support | 2018 |
| BDG Design (Holdings) Limited | Administrative & support | 2006 |
| BDG Design (South) Limited | Other services | 1993 |
| BDK Systems Limited | Construction | 1996 |
| Bdxcavations Ltd | Construction | 2023 |
| BE Green Tree Surgery Ltd | Agriculture & fishing | 2006 |
| BE Nourished Ltd | Other services | 2024 |
| BE Smart Media Ltd | Information & communication | 2010 |
| BE the Best YOU Clinic Ltd | Other services | 2023 |
| BE the Change Generation C.I.C. | Education | 2014 |
| Beach Vale (Overstrand) Management Company Limited | Households | 2017 |
| Beacon END Holdings Limited | Agriculture & fishing | 2013 |
| Beacon Heights Limited | Households | 1972 |
| Beacon Hill Homes Ltd | Construction | 2018 |
| Beacon Hill Property Investments Ltd | Real estate | 2020 |
| Beacon House Ministries | Health & social care | 1996 |