| Mestag Therapeutics Ltd | |
| Mestec Ltd | Berkshire |
| Meta Corporate Finance | |
| Meta Defence Labs | |
| Meta One Ltd | East Sussex |
| Metaboards | Oxfordshire |
| MetaCompliance | |
| Metadas Media | Wiltshire |
| MetadataWorks | |
| Metafore Software Design | Devon |
| Metafour UK Ltd | Greater London |
| MetaGallery.Ltd | Greater London |
| MetaHub | |
| Metail | |
| Metalchemy Ltd | |
| Metallobio Ltd | |
| Metalogic plc | Oxfordshire |
| Metalogics | |
| MetaMetrics | |
| Metamindz Ltd | |
| MetaOps Solutions | |
| Metapack | |
| Metaphysic | |
| Metaspeech | |
| Metavethics Institute | |
| MetCloud | |
| Metclouds Technologies Ltd | |
| Meteor IT Ltd | Lincolnshire |
| Meteoric Ltd | |
| metergrid GmbH | |
| Meterian Ltd | Greater London |
| Methera Global Communications Ltd | |
| Method & Class | |
| Method Grid | |
| Method4 | |
| Methodia Group | |
| MethodWorx Ltd | |
| Metis Labs | |
| Metix Medical | |
| Metofico | |
| Metomic | |
| Metranet Communications Ltd | |
| Metrikus Ltd | |
| Metrion Biosciences | |
| Metrion Biosciences | |
| Metrix Electronics Ltd | Hampshire |
| Metrodata | Surrey |
| Metryus Ltd | |
| MetServe Enterprises Ltd | Essex |
| Mettrr Technologies Ltd | |