| Blanco Visuals Ltd | London | 2025 |
| Blancpages Limited | London | 2024 |
| Blandford Literary Festival C.I.C. | Blandford | 2024 |
| Blandford Rugby Football Club Limited | Blandford Forum | 2010 |
| Blandycreative Limited | Hastings | 2019 |
| Blanedell Limited | Ruislip | 1972 |
| Blanify Ltd | London | 2025 |
| Blank Art LDN Limited | Manchester | 2024 |
| Blank Canvas by MD CIC | St. Helens | 2019 |
| Blank Canvas Entertainment Limited | Mattingley | 2013 |
| Blank Canvas Productions Ltd | Norwich | 2011 |
| Blank Canvas Theatre Limited | Kington | 2019 |
| Blank Inside. Limited | Lewes | 2013 |
| Blank Productions | Lewes | 2005 |
| Blank Script Limited | Edinburgh | 2018 |
| Blank Space Collective Ltd | London | 2025 |
| Blank Space Content Ltd | Manchester | 2025 |
| Blank Space Creative Studios Ltd | Nottingham | 2025 |
| Blank Space Liverpool Limited | Bootle | 2024 |
| Blank Studios Scotland Ltd | Helensburgh | 2025 |
| Blanket Tattoo Ltd | Glasgow | 2026 |
| Blankly Ltd | Norwich | 2025 |
| Blankney Golf Club Limited | Lincoln | 2024 |
| Blankney Sporting Ltd | Sleaford | 2026 |
| Blannicombe Valley Shoot Limited | Honiton | 2013 |
| Blas Cyfryngau Cymru CBC | Dinas Powys | 2023 |
| Blas Festival Ltd | Isle Of Skye | 2006 |
| Blasford Hill Fisheries Limited | Chelmsford | 2015 |
| Blast Amateur Boxing Academy CIC | Argyle Road | 2026 |
| Blast Beat Lighting Ltd | London | 2026 |
| Blast Communications Limited | Brighton | 1989 |
| Blast Fitness Camps Ltd | Lifton | 2012 |
| Blast Fitness Health and Wellbeing Limited | Bristol | 2022 |
| Blast Furnace Recording Studios Limited | Derry | 1995 |
| Blast OFF Events Ltd | Sturminster Newton | 2016 |
| Blast Radius Films Ltd | Leeds | 2025 |
| Blast Sport Ltd | Wareham | 2005 |
| Blast Theory | Brighton | 1996 |
| Blasterzone UK Ltd | Evesham | 2026 |
| Blastfitness Gym Limited | Ayr | 2015 |
| Blastfitt Limited | London | 2021 |
| Blasé Creative Ltd | Waltham Abbey | 2018 |
| Blatant Music Limited | London | 1992 |
| Blatant Touring Limited | London | 1997 |
| Blatella Films Ltd. | Corringham | 2016 |
| Blaven Studios Ltd | Royston | 2024 |
| Blaw Training Limited | South Croydon | 2018 |
| Blawearie Shoot Limited | Chathill | 2016 |
| Blaydon RFC Ltd | Newcastle Upon Tyne | 2008 |
| Blaydon Rugby Football Club Ltd | Newcastle Upon Tyne | 2017 |
| Blaydon Tennis Club Limited | Newcastle Upon Tyne | 1997 |
| Blaydon Trade Windows and Doors Limited | Newcastle Upon Tyne | 1996 |
| Blaze Ballers Sports Limited | Mildenhall | 2025 |
| Blaze Bayley Recording Ltd | Manchester | 2018 |
| Blaze Community Foundation | Sheffield | 2008 |
| Blaze Fitness UK Ltd | Fleet | 2019 |
| Blaze Studio Ltd | Bristol | 2003 |
| Blaze Trails CIC | London | 2021 |
| Blaze Virtual Reality Ltd | Burton-On-Trent | 2024 |
| Blazepark Limited | London | 1996 |
| Blazer Entertainment Limited | Bootle | 2017 |
| Blazin Fiddles Limited | Biggar | 2006 |
| Blazin Squad Ltd | Harlow | 2024 |
| Blazing Knuckles Limited | Harrow | 2025 |
| Blazing Padels Limited | Norwich | 2023 |
| BLC Music Limited | Borehamwood | 2016 |
| Blearred London Ltd | Abingdon | 2017 |
| Bleed Ltd | Abingdon | 2020 |
| Bleep Bloop Limited | London | 2022 |
| Blend Films Ltd | London | 2019 |
| Blend Leicester Ltd | Leicester | 2025 |
| Blend Lifestyle Limited | London | 2024 |
| Blend Pilates Ltd | Waltham Cross | 2025 |
| Blend Studios Ltd | Borehamwood | 2006 |
| Blendart Limited | Borehamwood | 1993 |
| Blended Production Limited | London | 2026 |
| Blended! Events Limited | Newcastle Upon Tyne | 2012 |
| Blender Collective Ltd | Barking | 2024 |
| Blenheim Art Foundation | Woodstock | 2013 |
| Blenheim Christmas Market Ltd | Portsmouth | 2024 |
| Blenheim Palace Heritage Foundation | Woodstock | 2015 |
| Blenheim Polo Ltd | Bicester | 2025 |
| Blenheim Visitors Limited | Woodstock | 2006 |
| Blenkhorns Boat Hire Limited | Harrogate | 2021 |
| Bless OUR Show Ltd | Sutton | 2026 |
| Blessed With Love Ltd | Borehamwood | 2017 |
| Bletchley Park Trust Limited | Milton Keynes | 1992 |
| Bletchley Rugby Club Limited | Milton Keynes | 2009 |
| Blether Forever C.I.C. | Manchester | 2025 |
| Blether Street Ltd | Paisley | 2025 |
| Bleu Blanc Ocean Racing Ltd | Egham | 2016 |
| Bleur Studios CIC | London | 2023 |
| Blewbury Riding & Training Centre Limited | Witney | 1985 |
| Blewtoof Ltd | Maidstone | 2022 |
| BLG Theatrical Ltd | London | 2023 |
| BLH Fitness Limited | Halesowen | 2020 |
| Blick Shared Studios | Belfast | 2007 |
| Blimation Limited | Wakefield | 2019 |
| Blimey Events Limited | Preston | 2021 |
| Blind Ditch Ltd | Exeter | 2008 |