Driving with prescribed medical cannabis involves more than just holding a...

https://www.bookmarking-maze.win/medical-cannabis-is-legal-but-the-2mcg-l-thc-limit-is-a-strict-roadside

Driving with prescribed medical cannabis involves more than just holding a prescription. While a medical defence exists for the 2µg/L THC limit, it isn't a free pass. Drivers must notify the DVLA and remain fully fit to operate their vehicle