| Blackstage Events Ltd | London | 2022 |
| Blackstage Ltd | Kington | 2020 |
| Blackstar Films Ltd | London | 2020 |
| Blackstar Live Limited | Basildon | 2011 |
| Blackstar London Limited | Rossendale | 2012 |
| Blackstar Management London Limited | Rossendale | 2021 |
| Blackstar Promotions Limited | London | 2018 |
| Blackstar Sporting Events Limited | Solihull | 2015 |
| Blackstock Community Boxing C.I.C. | Gloucester | 2026 |
| Blackstone Sports Group Ltd | Sheffield | 2021 |
| Blackstone Studios Ltd | Winlaton | 2012 |
| Blackstonegrappling Ltd | Dartford | 2025 |
| Blackthorn Marina Limited | Kettering | 2011 |
| Blackthorn Theatre Ltd | West Byfleet | 2019 |
| Blackthorne Productions Limited | Stoke Poges | 2006 |
| Blacktip Design Limited | Sheffield | 2011 |
| Blacktress UK CIC | London | 2024 |
| Blackwallstreet Promotion Ltd | London | 2021 |
| Blackwater Associates Limited | London | 2002 |
| Blackwater Health and Fitness Limited | Witham | 2014 |
| Blackwater Management Ltd | Liverpool | 2025 |
| Blackwater Marina Ltd | Croydon | 2001 |
| Blackwater Music Limited | Glasgow | 2013 |
| Blackwater Sailing Club Limited | Maldon | 1960 |
| Blackwater Valley Countryside Trust | Aldershot | 2003 |
| Blackwater Valley Golf Centre Limited | Middlesex | 2003 |
| Blackwell Adventure | Bromsgrove | 1980 |
| Blackwell Fitness Limited | Ipswich | 2008 |
| Blackwell Golf Club,Limited | Bromsgrove | 1922 |
| Blackwell Grange Golf Club Limited | Darlington | 1964 |
| Blackwell Mining and Mineral Engineering Limited | Nottingham | 1985 |
| Blackwell Sailing | Bowness On Windermere | 2004 |
| Blackwhiteblack Limited | London | 2015 |
| Blackwing Limited | Eye | 1975 |
| Blackwood Escape Limited | Blackwood | 2018 |
| Blackwood Golf Management Ltd | Bangor | 2015 |
| Blackwood RFC Limited | Blackwood | 2023 |
| Blackwood Stars Rugby Club Limited | Blackwood | 2025 |
| Blackzone Coaching Ltd | Hamilton | 2018 |
| Bladder and String Ltd | Coventry | 2019 |
| Blades Racing Team Limited | London | 2017 |
| Bladon Sports Limited | Bicester | 2024 |
| Blaenau Gwent Indoor Bowls Limited | Ebbw Vale | 2017 |
| Blaenau Gwent Young Stars Ltd. | Ebbw Vale | 2015 |
| Blaenavon Workmens Hall Limited | Pontypool | 2017 |
| Blaengarw Cricket Club Ltd | Bridgend | 2025 |
| Blafin Limited | Hackney | 2019 |
| Blagdon Valley GUN Club Limited | Bristol | 2004 |
| Blagsaey Arts CIC | Bristol | 2020 |
| Blah Blah Blah Scripts Ltd | Kingston Upon Thames | 2019 |
| Blaikie's Walks Limited | Perth | 2017 |
| Blaina Community Centre Ltd | Blaina | 2018 |
| Blaina Community Institute Ltd | Abertillery | 2016 |
| Blaina Community Sports Club Ltd | Blackwood | 2020 |
| Blaina RFC Limited | Blackwood | 2013 |
| Blair Atholl Village Hall | Pitlochry | 2016 |
| Blair Davies Limited | Burton-On-Trent | 2013 |
| Blair Productions Limited | Northampton | 2005 |
| Blair Russell Productions Ltd | London | 2023 |
| Blair SKI Hire & Active Breaks Ltd | Blairgowrie | 2011 |
| Blair Zaye Limited | London | 2017 |
| Blairdrummond Community Hall Association | Stirling | 2004 |
| Blairgowrie Community Project | Blairgowrie | 1998 |
| Blairgowrie Fitness Hub Ltd | Dundee | 2024 |
| Blairgowrie New Tennis Club | Blairgowrie | 2011 |
| Blairmore Village Trust Community Interest Company | By Dunoon | 2007 |
| Blaize | Barnard Castle | 1998 |
| Blaize Luxury Limited | Chadwell Heath | 2023 |
| Blak Box Music Group Ltd | Hornchurch | 2025 |
| Blak Planet Publishing Ltd | London | 2025 |
| Blakark Ltd | Cheltenham | 2002 |
| Blake Close Management Ltd | Chorley | 2019 |
| Blake Development Ltd | Bridgwater | 2024 |
| Blake Moore and Bond Ltd | Kington | 2015 |
| Blake Wilson Racing Ltd | London | 2025 |
| Blake's World Limited | Diss | 2016 |
| Blake-Frost Equestrian Services Ltd | Sandbach | 2022 |
| Blakeley Studio Ltd | Leyburn | 2023 |
| Blakemere Craft Centre Limited | Northwich | 1999 |
| Blakemere Events Limited | Northwich | 2017 |
| Blakenall Sporting Club Limited | Willenhall | 1989 |
| Blakeney Point Sailing School Limited | Holt | 1998 |
| Blakes Leisure Limited | Ingatestone | 2012 |
| Blakes Motivational Fitness Ltd | Haverfordwest | 2025 |
| Blakes TKS Ltd | Ilford | 2019 |
| Blakespills Limited | St Helens | 2025 |
| Blakestones Entertainment Ltd | Cardiff | 2019 |
| Blaklite Technical Limited | Northolt | 2018 |
| Blanc Canvas Balloons Limited | Thornton Heath | 2022 |
| Blanc Canvas Productions Ltd | Wigan | 2025 |
| Blanc Ceramic Ltd | London | 2025 |
| Blanc Events Worldwide Ltd | Manchester | 2021 |
| Blanc Festivals Ltd | Manchester | 2021 |
| Blanc Noir Consulting Ltd | London | 2020 |
| Blanca Yachting Ltd | London | 2023 |
| Blanche & George Enterprises Ltd | Droitwich | 2015 |
| Blanche Productions Limited | London | 2023 |
| Blanchflower Management Ltd | Broxbourne | 2017 |
| Blanchland Sporting Ltd | Gateshead | 2025 |
| Blanco Brothers Ltd | Hove | 2024 |