In 2018, UK cannabis law changed through the Misuse of Drugs Regulations 2001,...

https://bizzmarkblog.com/is-cannabis-decriminalised-anywhere-in-the-uk/

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