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

https://iris-wiki.win/index.php/Why_Did_Headlines_Say_Cannabis_Was_Legalised_in_2018%3F_Debunking_the_UK_Myth

In 2018, UK cannabis laws changed through updates to the Misuse of Drugs Regulations 2001, not the 1971 Act. This allowed specialist doctors to prescribe cannabis-based medicines like Sativex and Epidyolex under Schedule 2 rules