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

https://www.tntmagazine.com/leisure-entertainment/leisure/why-is-cannabis-still-illegal-in-the-uk-the-history-behind-medical-cannabis-law/

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