Medical cannabis has been legal in the UK since Nov 2018, but access is strict....

https://alpha-wiki.win/index.php/What_are_Cannabis-Based_Medicinal_Products_in_the_UK%3F_A_No-Nonsense_Guide

Medical cannabis has been legal in the UK since Nov 2018, but access is strict. You’ll need a specialist prescription, typically after standard treatments fail. NHS prescriptions are very rare, so most patients currently look to private clinics.