In 2018, UK cannabis law changed through an update to the Misuse of Drugs...

https://wiki-triod.win/index.php/Why_Was_the_2018_UK_Medical_Cannabis_Change_So_Narrow%3F

In 2018, UK cannabis law changed through an update to the Misuse of Drugs Regulations 2001, not the Misuse of Drugs Act 1971. This allowed specialist doctors to prescribe cannabis-based medicines like Sativex and Epidyolex