There’s no official government medical cannabis card. Access requires a...

https://direct-wiki.win/index.php/What_Follow-Up_Care_Do_Medical_Cannabis_Patients_Need_in_the_UK%3F

There’s no official government medical cannabis card. Access requires a specialist consultation and a review of your medical records. If prescribed, a card is optional; it simply serves as convenient proof of your lawful prescription when in public.