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

https://touch-wiki.win/index.php/Does_Having_a_Private_Prescription_Stop_Cannabis_Being_Illegal%3F

In 2018, UK cannabis law changed through updates 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 rules