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

https://wiki-tonic.win/index.php/What_is_the_Simplest_Summary_of_UK_Cannabis_Law_After_2018%3F

In 2018, UK cannabis law changed through updates to the Misuse of Drugs Regulations 2001, not the Misuse of Drugs Act 1971. Since then, specialist doctors can prescribe cannabis-based medicines listed as Schedule 2 substances