Legal medical cannabis isn't a free pass. You’re still bound by the 2μg/L THC...

https://www.yankee-bookmarkings.win/for-ev-drivers-using-medical-cannabis-a-prescription-offers-a-medical-defence

Legal medical cannabis isn't a free pass. You’re still bound by the 2μg/L THC limit and DVLA fitness standards. While a medical defence exists, it doesn’t override impairment. Legality never replaces your primary duty to ensure you’re safe to drive.