| Blue CAP Portslade Ltd | Hospitality | 2019 |
| Blue CAP ST Leonards Ltd | Hospitality | 2019 |
| Blue Cleaning Solutions (Liverpool) Limited | Administrative & support | 2011 |
| Blue Duck Partners Limited | Health & social care | 2022 |
| Blue Keith Limited | Information & communication | 2018 |
| Blue Monkey Tribe Ltd | Agriculture & fishing | 2020 |
| Blue Seal Properties Limited | Real estate | 1980 |
| Bluebells of Oxfordshire Ltd | Administrative & support | 2024 |
| Blueupgreendown Ltd | Professional & scientific | 2021 |
| Bluewater Pools Limited | Construction | 1997 |
| BMC Combustion Ltd | Construction | 2013 |
| Bmce Ltd | Construction | 2025 |
| BMG Topco Limited | Financial services | 2025 |
| Bmp.Blasters Ltd | Construction | 2007 |
| Bmsq Associates Limited | Professional & scientific | 2023 |
| BNT Property Limited | Households | 2026 |
| Bocabicester Ltd | Hospitality | 2025 |
| Bodyworks Dance & Fitness Ltd | Arts & recreation | 2021 |
| Boggart & Muppet | Professional & scientific | 2017 |
| Boho Burrito Ltd | Hospitality | 2020 |
| Boho Foods Limited | Extraterritorial | 2023 |
| Boleto Limited | Transport & logistics | 2024 |
| Bontob Limited | Wholesale & retail | 2019 |
| Boomerang Video Ltd | Administrative & support | 2005 |
| Booth & Phipps (Car Sales) Limited | Professional & scientific | 1984 |
| Bordon Development Holdings NO 2 Limited | Construction | 2021 |
| Boska Angela Personal Stylist Ltd | Other services | 2023 |
| Bosque Forest Ltd | Agriculture & fishing | 2022 |
| Botanicare Limited | Administrative & support | 2002 |
| Bound Biographies Limited | Administrative & support | 1991 |
| Bournefield Housing Ltd | Real estate | 2025 |
| Bournemark Property Developments Limited | Construction | 2022 |
| Bournemark Property Management Ltd | Construction | 2014 |
| Bournville Medical Ltd | Public administration | 2025 |
| Bower Close Limited | Households | 1996 |
| Bowwow Farmhouse Limited | Hospitality | 2019 |
| Boxercise Equipment Limited | Arts & recreation | 2004 |
| Boxercise Limited | Wholesale & retail | 1994 |
| Boyle Driver Services Ltd | Transport & logistics | 2010 |
| BP Trading Property Ltd | Hospitality | 2022 |
| BPI Decorating Ltd | Construction | 2023 |
| BPS Infotech Limited | Information & communication | 2004 |
| Bradbury Aviation LLP | | 2016 |
| Braf Village Limited | Wholesale & retail | 2025 |
| Brand Concepts Ltd | Administrative & support | 2023 |
| Branded Carpets Ltd | Wholesale & retail | 2002 |
| Branding by Design Limited | Professional & scientific | 2003 |
| Brandon's Clobber Limited | Wholesale & retail | 2026 |
| Brashfield Game Ltd | Agriculture & fishing | 2021 |
| Brashfield Management Limited | Households | 1981 |
| Braz Construction Ltd | Construction | 2025 |
| Brendon Leigh Racing Ltd | Information & communication | 2018 |
| Bressington Limited | Professional & scientific | 2020 |
| Brett Chambers Limited | Real estate | 2002 |
| Brial Ltd | Wholesale & retail | 2016 |
| Briardene Consultancy Limited | Administrative & support | 2016 |
| Bridgeways Global Projects (UK) Limited | Real estate | 2025 |
| Bridgland Road RTM Company Limited | Households | 2020 |
| Bright Earth Energy Ltd | Construction | 2024 |
| Bright Juniper Limited | Health & social care | 2026 |
| Bright Minds With Victoria Ltd | Education | 2025 |
| Bright Projects Limited | Information & communication | 2007 |
| Bright-Raven's Land Limited | Real estate | 2026 |
| Bright-Raven's Property Management Ltd | Extraterritorial | 2022 |
| Brightview Technologies UK Ltd | Information & communication | 2022 |
| Brihunet Ltd | Wholesale & retail | 2020 |
| Brincus Ltd | Transport & logistics | 2018 |
| Brita (UK) Limited | Wholesale & retail | 2014 |
| Brita Vivreau Limited | Administrative & support | 1993 |
| Brita Water Filter Systems Limited | Wholesale & retail | 1992 |
| Britelite Consulting Ltd | Education | 2019 |
| British Bakels Limited | Manufacturing | 1947 |
| British Grand Prix Limited | Professional & scientific | 1968 |
| Brittalent Solutions Ltd | Administrative & support | 2025 |
| Broad Canvas (Oxford) Limited | Wholesale & retail | 2020 |
| Broadcast Engineering Communications Ltd | Wholesale & retail | 2024 |
| Brogh Services Limited | Professional & scientific | 2022 |
| Brooke Kensington Ltd | Wholesale & retail | 1993 |
| Brooks Dairies Limited | Wholesale & retail | 2021 |
| Brown & Co Financial Planning Ltd | Financial services | 2023 |
| Brumani Limited | Real estate | 2018 |
| Bruneval Property Ltd | Real estate | 2018 |
| BS Yaagavi Ltd | Real estate | 2022 |
| BSC HQ Limited | Arts & recreation | 2024 |
| BTB Rentals Limited | Hospitality | 2026 |
| Bucca Hospitiality Limited | Wholesale & retail | 2023 |
| Buckie Walsh Limited | Financial services | 2022 |
| Buckingham Energy Ltd | Extraterritorial | 2014 |
| Buckingham Lofts Management Limited | Households | 2015 |
| Buckingham Utility Ltd | Administrative & support | 2014 |
| Buckland Maven Consulting Limited | Professional & scientific | 2024 |
| Buckle Data Consulting Ltd | Information & communication | 2024 |
| Bucknell Court Management Company Ltd | Hospitality | 2018 |
| Bucks Adlerian Training CIC | Education | 2026 |
| Building With Style Ltd | Construction | 2013 |
| Buildtech Construction Limited | Construction | 2022 |
| Bulldog Print Group Ltd | Manufacturing | 2021 |
| Bulls Head Garage Souldern Limited | Wholesale & retail | 2003 |
| Bumble BEE Media Limited | Information & communication | 2020 |
| Bumble Creatives CIC | Education | 2023 |