For EV drivers using medical cannabis, a prescription offers a medical defence...

https://www.bookmarkingtraffic.win/for-ev-drivers-using-prescribed-cannabis-understanding-the-law-is-vital-while

For EV drivers using medical cannabis, a prescription offers a medical defence but doesn't override the 2mcg/L THC limit. You must notify the DVLA of your fitness to drive. Remember: legality doesn’t replace responsibility—stay safe on the road.