| Blackhall Community Trust | Edinburgh | 2016 |
| Blackhall Tower Limited | Liverpool | 2019 |
| Blackham Engineering Design Limited | Warrington | 1998 |
| Blackhat Limited | Redhill | 2015 |
| Blackhaven Enterprises Limited | Kettering | 2017 |
| Blackhawk Sourcing Ltd | London | 2025 |
| Blackheath (T) Hairdressing Limited | Alton | 2024 |
| Blackheath Barbers Ltd | Blackheath | 2025 |
| Blackheath Cator Estate Residents Limited | London | 1965 |
| Blackheath Hairs Ltd | London | 2024 |
| Blackheath Nails Spa Ltd | London | 2024 |
| Blackheath Salon Ltd | Alton | 2025 |
| Blackheath Studio Fitness Ltd | Blackheath | 2017 |
| Blackheath Trading Limited | London | 2025 |
| Blackhill Windfarm Community Fund Limited | Duns | 2009 |
| Blackhills Residents' Association Limited | Esher | 1979 |
| Blackhorse Blackrod Holdings Limited | Salford | 2026 |
| Blackhorse Holdings Limited | Romford | 2009 |
| BLACKHORSE17 Ltd | London | 2025 |
| Blackiceberg Ltd | Colchester | 2010 |
| Blackie House Library and Museum | Edinburgh | 2022 |
| Blackjack Barbers Ltd | Kirkliston | 2024 |
| Blackjack Tanning Limited | Newcastle Upon Tyne | 2024 |
| Blackline Fitness Ltd | Ascot | 2023 |
| Blackline Systems Limited | London | 2012 |
| Blackline Vehicle Access Ltd | Kington | 2026 |
| Blackmere Investments Limited | Middleton | 2026 |
| Blackmillar Holdings Limited | Edinburgh | 2024 |
| Blackmillar Limited | Edinburgh | 2024 |
| Blackmore Business Solutions Ltd | Polegate | 2022 |
| Blackmore Vale Grain Limited | Chichesterd | 1985 |
| Blackmync Ltd | London | 2016 |
| Blackout & Belladonna Ltd | Lanark | 2025 |
| Blackout Barbers Ltd | Bridgend | 2023 |
| Blackpit Events Limited | Buckingham | 2025 |
| Blackpool & District Canine Society Ltd | Preston | 2013 |
| Blackpool Barber Pro Ltd | Blackpool | 2025 |
| Blackpool Blinds Limited | Blackpool | 2011 |
| Blackpool Boards Ltd | London | 2017 |
| Blackpool Business Improvement Districts Limited | Blackpool | 2021 |
| Blackpool Chamber of Trade Limited(The) | | 1937 |
| Blackpool Citizens Advice Bureau | Blackpool | 2009 |
| Blackpool Comfort Mobility Limited | Southport | 2018 |
| Blackpool Hair Salons Limited | Blackpool | 2023 |
| Blackpool Launderette Limited | Blackpool | 2024 |
| Blackpool Mobile Valeting Limited | Blackpool | 2015 |
| Blackpool Nails & Spa Ltd | Blackpool | 2026 |
| Blackpool Partnership Ltd | Salford | 2024 |
| Blackpool Rainbow Alliance C.I.C. | Blackpool | 2025 |
| Blackpool Retail Estates Limited | Salford | 2023 |
| Blackpool Tanning Company Ltd | Blackpool | 2023 |
| Blackpool Thai Ltd | Blackpool | 2020 |
| Blackpool Vehicle Preservation Group Limited | Fleetwood | 2003 |
| Blackraven Limited | Great Missenden | 2000 |
| Blackroom Studios Limited | Cardiff | 2018 |
| Blacks Barbering (Slateford) Ltd | Edinburgh | 2022 |
| Blacks Barbering Limited | Edinburgh | 2021 |
| Blacks Diamond Limited | Waterlooville | 2025 |
| Blacks Legal CLC Ltd | London | 2025 |
| Blacksea Trade Ltd | Waltham Abbey | 2024 |
| Blacksea Woods Limited | Edinburgh | 2014 |
| Blackshaw Nursery | London | 1992 |
| Blacksheep Hair Limited | Wolverhampton | 2015 |
| Blacksheep Property Limited | Liverpool | 2011 |
| Blackshore (Holdings) Limited | Luton | 2024 |
| Blacksmith&Sons Ltd | London | 2021 |
| Blacksphere Solutions Ltd | London | 2021 |
| Blackspring Ltd | London | 2023 |
| Blackstar Forex Networks Inc Limited | Belfast | 2013 |
| Blackstar Redemption Ltd | London | 2011 |
| Blackstar Warranties Ltd | London | 2025 |
| Blackstock Cleaners Limited | London | 2025 |
| Blackstone Chambers Limited | East Grinstead | 1998 |
| Blackstone Concierge Ltd | London | 2023 |
| Blackstone Detailing Ltd | West Drayton | 2024 |
| Blackstone Energy Group Ltd | Bristol | 2025 |
| Blackstone Global Group Ltd | Luton | 2020 |
| Blackstone Global Ltd | London | 2017 |
| Blackstone Hair Limited | Ipswich | 2021 |
| Blacktax Radio Taxis Limited | Blackpool | 1989 |
| Blackthorn Legal Associates Limited | Ilford | 2025 |
| Blackthorn Plant Hire Limited | Basildon | 2021 |
| Blackthorn Procurement Limited | Greenford | 2017 |
| Blackthorn Timber Limited | Bedlington | 2015 |
| Blackthorn Wellness Limited | London | 2026 |
| Blackthorne Ltd | Dundee | 2025 |
| Blacktop Solutions Limited | Nottingham | 2021 |
| Blackwalk Consultancy Ltd. | Kirknewton | 2020 |
| Blackwall Hire Limited | London | 2004 |
| Blackwall Labs Limited | London | 2011 |
| Blackwall Reach Trust | Tetbury | 2019 |
| Blackwardine Boarding Kennels & Cattery Ltd | Hereford | 2006 |
| Blackwater Country Events Limited | Chelmsford | 2013 |
| Blackwater Geological Consulting Limited | Wirral | 2018 |
| Blackwater International Ltd | York | 2019 |
| Blackwater Kitchens Limited | Basildon | 2020 |
| Blackwater Scaffolding Limited | Maldon | 2000 |
| Blackwax Ltd | Harrow | 2018 |
| Blackwell Community Hall CIC | Bromsgrove | 2021 |
| Blackwell Haulage Ltd | Pontefract | 2020 |