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

https://highstylife.com/can-i-qualify-for-medical-cannabis-if-i-had-bad-side-effects-from-meds/

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.