| Black House Studio Ltd | Professional & scientific | 2026 |
| Black Onyx Property Solutions Limited | Real estate | 2023 |
| Black Rhino Social Club Derby Ltd | Health & social care | 2025 |
| Black Rose BM Ltd | Wholesale & retail | 2020 |
| Black Sheep Media Haus Ltd | Professional & scientific | 2025 |
| Black Shoe Limited | Construction | 2002 |
| Black Tint Ltd | Transport & logistics | 2024 |
| Black Wolf Developments Limited | Real estate | 2024 |
| Blackbrook Lodges Limited | Hospitality | 2022 |
| Blackburn Developments (Midlands) Limited | Construction | 2022 |
| Blackburn Flat Roofing Ltd | Construction | 2026 |
| Blackburn Joinery and Roofing Ltd | Construction | 2026 |
| Blackdog Rail Ltd | Professional & scientific | 2024 |
| Blackfield Green Estate Management Company Limited | Households | 2018 |
| Blackheath Building Consultancy Limited | Professional & scientific | 2016 |
| Blackmill Clothing Limited | Wholesale & retail | 2015 |
| Blackout Security Services Ltd | Administrative & support | 2025 |
| Blackseal Solutions Ltd | Construction | 2023 |
| Blacksmith Properties Limited | Real estate | 2015 |
| Blacksmiths Hospitality Ltd | Wholesale & retail | 2021 |
| Blackstone Innovations Ltd | Manufacturing | 2024 |
| Blackthorn Property Services Ltd | Construction | 2025 |
| Blackwell Commercial Ltd | Wholesale & retail | 2026 |
| Blackwell Holdings Limited | Wholesale & retail | 2016 |
| Blackwell Medical Services Limited | Health & social care | 2006 |
| Blacroft Holdings Ltd | Professional & scientific | 2021 |
| Blades Darts Ltd | Wholesale & retail | 2025 |
| Blagreaves Hand Car Wash Limited | Other services | 2018 |
| Blair Gratton Architects Limited | Professional & scientific | 2002 |
| Blakeley Property Limited | Real estate | 2004 |
| Blakemore’S Specialist Contractors Ltd | Construction | 2019 |
| Blakeney Green Management Company Limited | Households | 2024 |
| Blakewood Emran Quantity Surveyors Limited | Extraterritorial | 2017 |
| Blanchard Pest Management Ltd | Administrative & support | 2025 |
| Blank Creative Ltd | Information & communication | 2025 |
| Blarney Burger Company Ltd | Hospitality | 2024 |
| Blast Workz Ltd | Professional & scientific | 2024 |
| Blaze Arts and Entertainment Limited | Hospitality | 2012 |
| Blend Beauty Limited | Other services | 2014 |
| Blend Training Academy Limited | Education | 2025 |
| Blenheim House Limited | Administrative & support | 2020 |
| Blessed Beauties Limited | Other services | 2025 |
| Blessed Recruitment Solutions Ltd | Administrative & support | 2017 |
| BLG Scaffolding Ltd | Construction | 2026 |
| BLH Electrical Installations Ltd | Construction | 2010 |
| BLH Property Services Limited | Construction | 2018 |
| Blind Screen Limited | Manufacturing | 2022 |
| Blind Screen Ventures Ltd | Financial services | 2023 |
| Bling Hub Collection Ltd | Wholesale & retail | 2026 |
| Blingy Bear Cleanex Ltd | Transport & logistics | 2025 |
| Bliss Property Rentals Limited | Real estate | 2020 |
| Bliss Wedding DJ Limited | Information & communication | 2015 |
| Blissful Stays Ltd | Real estate | 2024 |
| Blissow Limited | Hospitality | 2025 |
| Blitz Hygiene Services Ltd | Real estate | 2006 |
| Blitzmyplace Ltd | Administrative & support | 2017 |
| BLL Derby Ltd | Real estate | 2012 |
| BLN Transport Limited | Transport & logistics | 2010 |
| Bloc Creative Ltd | Extraterritorial | 2020 |
| Bloc Digital Ltd | Information & communication | 2005 |
| Bloc Graphics Limited | Extraterritorial | 2018 |
| Bloc Holdings Ltd | Financial services | 2013 |
| Bloc Media Ltd | Professional & scientific | 2019 |
| Blochub Ltd | Information & communication | 2020 |
| Blockbuster Launch Limited | Wholesale & retail | 2025 |
| Blockmed Consultancy Limited | Professional & scientific | 2020 |
| Blockpharm Ltd | Professional & scientific | 2022 |
| Blockpost Software Ltd | Information & communication | 2013 |
| Blocline Properties Ltd | Real estate | 2026 |
| Blok 663 Limited | Construction | 2023 |
| Blok 841 Limited | Construction | 2023 |
| Bloods and Beyond Ltd | Health & social care | 2023 |
| Bloodstock Tours Limited | Arts & recreation | 2018 |
| Blooming Beauty by SK Ltd | Other services | 2025 |
| Blooming Care Ltd | Health & social care | 2023 |
| Bloomstead Care Ltd | Administrative & support | 2024 |
| Blossom Apparel Ltd | Wholesale & retail | 2023 |
| Blossom Financial Planning Ltd | Financial services | 2020 |
| Blossoms Derby Ltd | Wholesale & retail | 2025 |
| Blount's Clay Shooting Ltd | Arts & recreation | 2020 |
| BLU Diamond Property Group Ltd | Real estate | 2023 |
| BLU Sky Construction Limited | Construction | 2022 |
| Blue (Eco) Ltd | Agriculture & fishing | 2021 |
| Blue Apple Ltd | Information & communication | 2024 |
| Blue Box Therapy Limited | Professional & scientific | 2024 |
| Blue Care Services Ltd | Administrative & support | 2019 |
| Blue Castle Solutions Ltd | Information & communication | 2012 |
| Blue Chimes Estate Holdings Ltd | Real estate | 2024 |
| Blue Dog Express Couriers Ltd | Transport & logistics | 2025 |
| Blue Earth Environmental Solutions Ltd | Transport & logistics | 2026 |
| Blue Forest Digital Limited | Information & communication | 2022 |
| Blue Grain Partnership Limited | Professional & scientific | 2009 |
| Blue Grid Technologies Ltd | Information & communication | 2025 |
| Blue Iris Boutique Ltd | Wholesale & retail | 2025 |
| Blue Light Engineering Ltd | Wholesale & retail | 2024 |
| Blue Lion Property Management Limited | Real estate | 2018 |
| Blue Lion Training Academy Limited | Professional & scientific | 2017 |
| Blue Mountain Adventures Limited | Health & social care | 2020 |
| Blue Mountain Education Company Limited | Education | 2005 |
| Blue Mountain Homes Ltd. | Health & social care | 2002 |