| Best Business Loans Ltd | Information & communication | 2025 |
| Better Homes East Anglia Ltd | Real estate | 2026 |
| Betts International Limited | Manufacturing | 1998 |
| Betts Limited | Manufacturing | 1998 |
| Beyond Limits Coaching With Chantelle Ltd | Arts & recreation | 2025 |
| Bice Limited | Construction | 2018 |
| Big Robot Ltd | Information & communication | 2010 |
| BIGFISH27 Ltd | Transport & logistics | 2018 |
| Bill and Berts Ltd | Wholesale & retail | 2019 |
| BIM Bureau Limited | Information & communication | 2016 |
| Binibabies Ltd | Wholesale & retail | 2019 |
| Binwash UK Limited | Other services | 2010 |
| Bird in Hand Apartments | Administrative & support | 2024 |
| Bish Enterprises Limited | Wholesale & retail | 2025 |
| Bishers Limited | Real estate | 2025 |
| BKS Tradeline Limited | Wholesale & retail | 2010 |
| Black Oak Groundworks Ltd | Construction | 2022 |
| Black Skull Creative Limited | Administrative & support | 2015 |
| Black Skull Productions Limited | Arts & recreation | 2013 |
| Black Skull Studio Limited | Arts & recreation | 2020 |
| Black Skull Talent Limited | Arts & recreation | 2024 |
| Black Swan Nutrition Limited | Wholesale & retail | 2026 |
| Black Swan Physical Training Ltd | Other services | 2024 |
| Blacksurv Limited | Professional & scientific | 2013 |
| Blackwater Fire Solutions Limited | Public administration | 2025 |
| Blackys Recovery Ltd | Wholesale & retail | 2016 |
| Blissful Tattoos Ltd | Other services | 2023 |
| Blonde Ambition Salon Ltd | Other services | 2025 |
| Blossom Chinese Limited | Hospitality | 2024 |
| Blri Properties Ltd | Extraterritorial | 2022 |
| Blue Gooseberry Merchandise Ltd | Wholesale & retail | 2016 |
| Bluebell Cemetery & Crematorium Ltd | Other services | 2024 |
| Bluestone Recycling Limited | Manufacturing | 2009 |
| Bobby Bobs Salon & Boutique Ltd | Other services | 2022 |
| Bocking Riverside Management Limited | Real estate | 2015 |
| Boddington IP Limited | Manufacturing | 2008 |
| Bonsen Limited | Hospitality | 2025 |
| Bookkeeper's Detox Ltd | Other services | 2022 |
| Booth Long Enterprise Ltd | Hospitality | 2025 |
| Booziebay Drinks Co Ltd | Wholesale & retail | 2024 |
| Bourlet & SON Limited | Construction | 2020 |
| Bourlet Solutions Ltd | Professional & scientific | 2018 |
| Bourne Farm (Halstead) Limited | Agriculture & fishing | 1949 |
| Bowyer Properties Group Ltd | Real estate | 2021 |
| Braemore Signs ( Ipswich ) Ltd. | Professional & scientific | 2016 |
| Braemore Signs Limited | Professional & scientific | 2009 |
| Braintree Electrical Services Ltd | Construction | 2023 |
| Braintree Electro Platers Limited | Manufacturing | 1971 |
| Braintree Joinery Ltd | Manufacturing | 2022 |
| Braintree Loft Conversions Limited | Construction | 2003 |
| Breen's Gym Ltd | Arts & recreation | 2024 |
| Brentham Furnishers (Ealing) Limited | Wholesale & retail | 1986 |
| Brereton Jackson Financial Limited | Financial services | 2015 |
| Brett IT Consulting Ltd | Information & communication | 2023 |
| Bri-Chez Bulk Haulage Limited | Water & waste | 2022 |
| Brickpath Properties Limited | Real estate | 2026 |
| Brickwork Estimating and Commercial Services Ltd | Construction | 2021 |
| Bright Cave Cleaning Solutions Ltd | Administrative & support | 2026 |
| Broadway Close (NOS 7 to 15) Maintenance Limited | Households | 1962 |
| Brokura Limited | Financial services | 2026 |
| Bromley Common Properties LLP | | 2016 |
| Brook Consulting (2023) Limited | Professional & scientific | 2023 |
| Brooks Management Consultancy Ltd | Real estate | 2021 |
| Broomfield Gardens Management Company Limited | Hospitality | 2007 |
| Bruff Cafe Limited | Hospitality | 2021 |
| Brushwood Limited | Construction | 2018 |
| Buff Naked Ltd | Manufacturing | 2025 |
| Building & Structural Consultants Limited | Construction | 2006 |
| Burwell Developments Ltd | Construction | 2022 |
| Burywood Property Consultants Ltd | Construction | 2007 |
| Busfield Court Management Ltd | Real estate | 2022 |
| Business Rescue (UK) Commercial Debt Management Limited | Professional & scientific | 2013 |
| BW Building & Construction Ltd | Construction | 2024 |
| BW Property Development Limited | Construction | 2021 |
| C & M Clacton Limited | Hospitality | 2019 |
| C & M Colchester Limited | Extraterritorial | 2019 |
| C & M Maldon Limited | Hospitality | 2019 |
| C & M Newmarket Limited | Hospitality | 2019 |
| C & M Restaurant Group Limited | Financial services | 2019 |
| C & S Automation Limited | Manufacturing | 2004 |
| C & S Ltd | Administrative & support | 2019 |
| C - Cubed Consulting Limited | Administrative & support | 2015 |
| C H Communications Limited | Professional & scientific | 2015 |
| C J Smith Welding Limited | Construction | 2008 |
| C O Service Limited | Construction | 2014 |
| C W Coachworks Limited | Wholesale & retail | 2023 |
| C&M Contractors Ltd | Administrative & support | 2025 |
| C.D. James Ltd | Agriculture & fishing | 2002 |
| Cafe Bijou Limited | Manufacturing | 2021 |
| Cafe Grill & Smash Burger Limited | Hospitality | 2025 |
| Calm Installations Limited | Construction | 2021 |
| Cambridge Sports & Spine Imaging Limited | Health & social care | 2017 |
| Cammas Ltd | Professional & scientific | 2021 |
| Cane Construction Limited | Construction | 1997 |
| Cann Plumbing and Heating Ltd | Construction | 2025 |
| Caoimhe and Cleans Ltd | Administrative & support | 2025 |
| Capital Door Services Limited | Manufacturing | 2008 |
| Capital Doors UK Ltd | Manufacturing | 2021 |
| Capital Road Safety Ltd | Professional & scientific | 2008 |
| Carabow Commercial Ltd | Financial services | 2010 |