Medical cannabis users face complex road rules. While a medical defence exists...

https://evpowered.co.uk/feature/medical-cannabis-and-uk-driving-laws-what-ev-owners-must-know/

Medical cannabis users face complex road rules. While a medical defence exists for the 2µg/L THC limit, you must meet DVLA fitness standards. Always remember: legality does not replace responsibility; a prescription is no safety guarantee