Medical cannabis users have a defence for the 2mcg/L THC limit, yet you must...
https://www.mediafire.com/file/rkpx0pv3x6lgq5k/pdf-25878-69659.pdf/file
Medical cannabis users have a defence for the 2mcg/L THC limit, yet you must still meet DVLA fitness-to-drive rules. Legality isn't a substitute for responsibility; being prescribed doesn't exempt you from impairment laws