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

https://ace-wiki.win/index.php/Why_Does_My_NHS_Experience_with_Medical_Cannabis_Differ_by_UK_Nation%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 under Schedule 2