Medical cannabis is legal, but roadside tests don’t distinguish between...

https://oscar-wiki.win/index.php/Is_It_Risky_to_Drive_Right_After_Taking_My_Dose_Even_If_I_Feel_Normal%3F

Medical cannabis is legal, but roadside tests don’t distinguish between prescription and illicit use. Stay under the 2mcg/L THC limit or rely on the medical defence. DVLA fitness standards still apply