| Blossoms Bees Ltd | Weymouth | 2025 |
| Blossoms Vision Technology Limited | Beckenham | 2024 |
| Blount Shutters Limited | Maldon | 1984 |
| Blove Sacred Sound Ltd | Llandysul | 2025 |
| Blow E-Lixir Ltd | Liverpool | 2017 |
| Blow Moulding Technologies Ltd | Belfast | 2011 |
| Blowfish Bespoke Limited | Dudley | 2023 |
| Blowfish Glass Ltd | Dudley | 2020 |
| Blowfish Media Limited | Coventry | 2007 |
| Blowing Dandelion Limited | London | 2016 |
| Blown Away Pictures Ltd | London | 2019 |
| Blowpack Ltd | Blackburn | 2024 |
| Blowplast Limited | High Wycombe | 1988 |
| Blox Manufacturing Ltd | Hednesford | 2021 |
| Bloxhams Goods Ltd | Covent Garden | 2025 |
| Bloxo Limited | Chichester | 2023 |
| Bloxt Energy Ltd | Liverpool | 2023 |
| Bloxwich Aluminium Casting Co.Limited | Wolverhampton | 1969 |
| Bloxwich Linishing and Fettling Limited | Burntwood | 2017 |
| Bloxwich Metal Finishing Co. Limited | Walsall | 1981 |
| Bloxwich Trading Limited | Worcestershire | 2006 |
| Bloxwich Transport & Container Products Limited | Worcestershire | 2006 |
| BLP (Northern) Limited | Benton | 1991 |
| BLR Consulting Limited | Aberdeen | 2018 |
| BLR Fabrications Limited | Grimsby | 2024 |
| BLR Services Limited | Bedford | 2024 |
| BLR Yorkshire Ltd | Bradford | 2023 |
| BLS (EA) Limited | Great Yarmouth | 2023 |
| BLS Conversions Limited | Fengate | 2017 |
| BLS Developments Ltd | Kingsbridge | 2011 |
| BLS Engineering Ltd | York | 2011 |
| BLS Sportswear & PPE Equipment Limited | Milton Keynes | 2021 |
| BLS Wholesale Ltd | Exeter | 2022 |
| Blsx PVT. Ltd | Crowthorne | 2022 |
| BLT Italy Ltd | Cambridge | 2025 |
| Bltz Nutrition Limited | London | 2026 |
| BLU Bakes Ltd | Cradley Heath | 2024 |
| BLU Banana Graphics Limited | Nottingham | 2017 |
| BLU Bear Moto Ltd | Southampton | 2024 |
| BLU Beri Ltd | Ross-On-Wye | 2011 |
| BLU Carpentry Ltd. | Cardiff | 2017 |
| BLU Chem Ltd | Strabane | 2017 |
| BLU Crafts Ltd | Leicester | 2024 |
| BLU Gekko Limited | Sheffield | 2020 |
| BLU Goblin Ltd | London | 2021 |
| BLU Jewellery Limited | Stanmore | 2025 |
| BLU Magic Sauces Ltd | Birmingham | 2023 |
| BLU Marine Ltd | Eastleigh | 2007 |
| BLU Ocean Innovations UK Limited | London | 2026 |
| BLU Print & Design Limited | Whitley Bay | 2017 |
| BLU Retail Ltd | Wallasey | 2021 |
| BLU Rooster Ltd | London | 2016 |
| BLU Sky Poultry Limited | Norwich | 2016 |
| BLU Sky Studios Ltd | Loughton | 2026 |
| BLU Sky Technical Services Ltd | Uttoxeter | 2024 |
| BLU TEC Fasteners Limited | Croydon | 2015 |
| BLU Thomas Ltd | Swansea | 2015 |
| BLU Thomas Medical Ltd | Swansea | 2019 |
| BLU Wireless Technology Limited | Bristol | 2009 |
| Bluarc Fabrications Limited | Gloucester | 2013 |
| Blubug Ltd. | Emsworth | 2008 |
| Bludog Ltd | Coventry | 2013 |
| Blue & Bear Ltd | Witney | 2026 |
| Blue & Co Ltd | London | 2014 |
| Blue & Green Marine Commercial Solutions Limited | Witney | 2009 |
| Blue & Green Marine International Limited | Eynsham | 2009 |
| Blue Aardvark Joinery Limited | Billingham | 2008 |
| Blue Abundance Limited | London | 2018 |
| Blue Acoustic Ltd | Shrewsbury | 2023 |
| Blue Aero (N.I.) Ltd | Larne | 2018 |
| Blue Affix Limited | London | 2016 |
| Blue Apple Printing Ltd | Manchester | 2012 |
| Blue Aqua Investments Limited | Birmingham | 2019 |
| Blue Army Ltd | Leicester | 2024 |
| Blue Aspirations Ltd | London | 2025 |
| Blue Associates Sportswear Limited | Tring | 2018 |
| Blue Asteroids Ltd | Manchester | 2018 |
| Blue Attach Limited | Stirling | 2017 |
| Blue Badge Designs Ltd | Nottingham | 2004 |
| Blue Badge Protector Limited | London | 2016 |
| Blue Banana (On-Line) Limited | London | 2004 |
| Blue Bark (Leicester) Ltd | Nottingham | 2023 |
| Blue Bear Aviation Limited | Eastleigh | 2018 |
| Blue Bear Necessities Limited | Peterborough | 2015 |
| Blue BEE Brewery Ltd | Sheffield | 2010 |
| Blue Bench Enterprise Ltd | London | 2008 |
| Blue Birds Bakes Ltd | Westerham | 2025 |
| Blue Blacks London Ltd | Northolt | 2022 |
| Blue Box Design and Laser Servicing Limited | Wellingborough | 2022 |
| Blue Box Design Limited | Port Glasgow | 1995 |
| Blue Box One Limited | Farnborough | 2004 |
| Blue Box Studios London Ltd | London | 2018 |
| Blue Brand Ltd | London | 2024 |
| Blue Brick Concrete & Aggregates Limited | Sheffield | 2017 |
| Blue Bubble Ltd | Bury St. Edmunds | 2021 |
| Blue Buddha Seeds Ltd | Croydon | 2019 |
| Blue Butterfly Entertainment Ltd | London | 2019 |
| Blue C Mobile Limited | Glasgow | 2017 |
| Blue Cart Promotions Ltd | Glasgow | 2023 |
| Blue Castle Studio Ltd | Worthing | 2020 |