| Boum Digital Limited | Information & communication | 2024 |
| Boum Limited | Real estate | 2024 |
| Boum Property Solutions Ltd | Real estate | 2024 |
| Bounce Tickets Limited | Administrative & support | 2021 |
| Boundary Consulting Ltd | Professional & scientific | 2022 |
| Bourn Again Ltd | Agriculture & fishing | 2026 |
| Bourne Friars Holding Ltd | Financial services | 2026 |
| Bourne View (Ipswich) Management Company Limited | Households | 2020 |
| BOURNE4X4 Ltd | Wholesale & retail | 2025 |
| Bourton Ventures Ltd | Financial services | 2023 |
| Bouw Group Limited | Real estate | 2025 |
| Bovine Games Ltd | Information & communication | 2024 |
| Bowbeck Consulting Limited | Information & communication | 2013 |
| Bowbro Limited | Professional & scientific | 2005 |
| Bowdery Bros Ltd | Construction | 2021 |
| Bowen Investment Holdings Ltd | Real estate | 2023 |
| Bower Works Ltd | Professional & scientific | 2026 |
| Bowers Builders Limited | Construction | 2017 |
| Bowldilocks Ltd | Wholesale & retail | 2026 |
| Bowman Business Services Ltd | Construction | 2025 |
| Box and Store Ltd | Transport & logistics | 2024 |
| Box Architects Holdings Ltd | Professional & scientific | 2010 |
| Box Bars Group Ltd | Hospitality | 2025 |
| Boxhill Properties Limited | Hospitality | 2023 |
| Boxology Marketing Limited | Professional & scientific | 2023 |
| Boyangtrade Ltd | Wholesale & retail | 2026 |
| BRA Group Ltd | Financial services | 2025 |
| Brabazon Morris Limited | Real estate | 2019 |
| Bradfield Hall Management Company Limited | Households | 1992 |
| Bradley and Malvina Property Limited | Real estate | 2017 |
| Braintech IT Service Limited | Information & communication | 2025 |
| Braintree Commercials Ltd | Wholesale & retail | 2024 |
| Braintxai Limited | Professional & scientific | 2021 |
| Bralton Roofing Ltd | Construction | 2021 |
| Bram Data Ltd | Information & communication | 2021 |
| Bramble Brook Holiday Club Ltd | Health & social care | 2021 |
| Bramwellpartners Ltd | Wholesale & retail | 2025 |
| Branched Nutrition Ltd | Manufacturing | 2024 |
| Brand Crafting Ltd | Professional & scientific | 2024 |
| Brand Ideators Limited | Extraterritorial | 2024 |
| Brand Playground Ltd | Professional & scientific | 2023 |
| Brandia Marketing Ltd | Information & communication | 2025 |
| Brandifies Ltd | Information & communication | 2024 |
| Brandify Digital Ltd | Information & communication | 2025 |
| Brandoptimise Ltd | Professional & scientific | 2024 |
| Brands Nest Ltd | Wholesale & retail | 2018 |
| Brandship Direct E-Commerce Ltd | Wholesale & retail | 2023 |
| Branverse Ltd | Wholesale & retail | 2025 |
| Branwell Group Ltd | Education | 2025 |
| Brar Capital Ltd | Financial services | 2025 |
| Brava Coaching and Consulting Ltd | Professional & scientific | 2025 |
| Brave ARK Properties Limited | Real estate | 2026 |
| Bravexa Ltd | Other services | 2025 |
| Bravo Online Selling Ltd | Wholesale & retail | 2025 |
| Bravo Travel BSE Ltd | Transport & logistics | 2025 |
| Brayfield Construction & Interiors Limited | Construction | 1991 |
| Brazierfamilyinns Ltd | Hospitality | 2024 |
| BRC Labs Ltd | Information & communication | 2026 |
| Breakthrough Education Ltd | Education | 2020 |
| Breastfeeding & Baby Support West Norfolk CIC | Health & social care | 2024 |
| Breathe Centric Ltd | Administrative & support | 2020 |
| Breckland Barns Ltd | Wholesale & retail | 2023 |
| Breckland Court Management Company (NO.2) Limited | Households | 1990 |
| Breijer Consultancy Ltd | Professional & scientific | 2026 |
| Bress Holdings Ltd | Financial services | 2021 |
| Brett Gooch Travel Limited | Administrative & support | 2023 |
| Brevlix Properties Ltd | Real estate | 2024 |
| Brew and Bowl Ltd | Hospitality | 2025 |
| Brewmate Ltd | Wholesale & retail | 2025 |
| Brewrat Limited | Hospitality | 2018 |
| Brewshed Ltd | Manufacturing | 2016 |
| Brian Spink Holdings Limited | Other services | 2015 |
| Brickfield Holdings (East Anglia) Limited | Financial services | 2025 |
| Brickfound Wealth Ltd | Real estate | 2025 |
| Brickify Ltd | Manufacturing | 2023 |
| Brickio Ltd. | Other services | 2024 |
| Brickwork Formation Ltd | Construction | 2021 |
| Bridge House Imaging Limited | Health & social care | 2023 |
| Bridge Street Securities Limited | Financial services | 2014 |
| Bridge the GAP Studios CIC | Professional & scientific | 2020 |
| Bridge Way Commerce Ltd | Wholesale & retail | 2026 |
| Bridgegrove Investments Limited | Hospitality | 2021 |
| Bridgestone Advisory Limited | Real estate | 2025 |
| Bridgetwin Ltd | Real estate | 2026 |
| Bridgewell Civil Ltd | Professional & scientific | 2026 |
| Briefkit Ltd | Information & communication | 2026 |
| Brierley Investments Limited | Real estate | 2025 |
| Bright & Found Ltd | Wholesale & retail | 2026 |
| Bright Beauty & Hair Ltd | Other services | 2025 |
| Bright Beauty Clinic Ltd | Other services | 2024 |
| Bright Flooring Solutions Ltd | Construction | 2015 |
| Bright Ideas Marketing Limited | Wholesale & retail | 1995 |
| Bright Notions Ltd | Information & communication | 2023 |
| Bright Tokens Ltd | Information & communication | 2025 |
| Brightandfox Limited | Administrative & support | 2017 |
| Brightaura Limited | Real estate | 2026 |
| Brightmade Trading Ltd | Wholesale & retail | 2025 |
| Brighton Brew Co Ltd | Manufacturing | 2024 |
| Brightwave Marketing Ltd | Professional & scientific | 2018 |
| Brightwell Lakes Residents Management Company Limited | Households | 2023 |