In 2018, UK cannabis law was updated through changes to the Misuse of Drugs...

https://dlf-ne.org/what-international-treaties-affect-uk-cannabis-law/

In 2018, UK cannabis law was updated through changes to the Misuse of Drugs Regulations 2001—not the Misuse of Drugs Act 1971—to allow specialist doctors to prescribe cannabis-based medicines listed under Schedule 2