Medical cannabis has been legal since 2018, though it isn't a first-line...

https://doctiplus.net/arthritis-and-medical-cannabis-can-uk-patients-get-a-prescription/

Medical cannabis has been legal since 2018, though it isn't a first-line treatment for arthritis. Access requires a specialist assessment, typically through private clinics, as NHS prescriptions are rare. Please discuss options with a professional.