| Blackbone IT Group | Lancashire |
| Blackbullion | |
| Blackburn Circuit Design Ltd | Greater Manchester |
| Blackburn College | |
| Blackburn Communications | |
| BlackCurve Solutions Ltd | |
| Blackford Analysis | |
| Blackford Analysis | |
| Blacklight Software | |
| Blackpool and The Fylde College | |
| BlackScore | |
| Blacksmith Marketing Consultancy | |
| Blackstar Solutions Ltd | |
| BlackSwan Technologies | |
| Blades Advertising & Marketing Ltd | |
| BlakBear | Greater London |
| Blake Simpson | |
| Blakelan Communications Ltd | East Sussex |
| BlaO | |
| Blastech Ltd | |
| Blayney Partnership | |
| Blaze Networks Ltd | Cheshire |
| Blazie | Buckinghamshire |
| Blazing Griffin | |
| Bleam Cyber Security | |
| Blend Commerce | Warwickshire |
| Blend Media | |
| Blenheim Chalcot | |
| Blenheim IT | Hertfordshire |
| Bletchley Park | Buckinghamshire |
| Blick Shared Studios | |
| BlindMatrix Ltd | Buckinghamshire |
| Blink Digital | |
| Blink Payment | |
| Blippar | Greater London |
| Blipstar | Worcestershire |
| BLISS | Greater Manchester |
| Bliss Systems | |
| Blitz Security Systems | Surrey |
| Blix Ltd | Channel Islands |
| Blk - The Commodity Marketplace Ltd | |
| Blockchain Expo World Series | |
| Blockchainology | |
| BlockchainReporter | |
| Blocksmith | Greater London |
| Blocs | |
| Bloktopia | |
| Blokur | |
| Blonde Soft Ltd | |
| Bloom Procurement Services Ltd | |