Medical cannabis has been legal in the UK since 2018 for specific conditions....

https://station-wiki.win/index.php/Is_It_Normal_to_Need_Patience_with_UK_Medical_Cannabis_Treatment%3F

Medical cannabis has been legal in the UK since 2018 for specific conditions. Obtaining a prescription requires a formal assessment by a specialist doctor. You must provide medical records confirming at least two failed prior treatments