Medical cannabis has been legal in the UK since 2018 via specialist private...

https://highstylife.com/is-medical-cannabis-a-performance-tool-for-runners-or-just-treatment/

Medical cannabis has been legal in the UK since 2018 via specialist private clinics. Eligibility requires a diagnosed condition and evidence of prior failed treatments. For runners, it is vital to note that WADA strictly prohibits THC during competition