Legality isn’t an excuse for impairment. If you drive with medical cannabis,...

https://star-wiki.win/index.php/The_Motorist%E2%80%99s_Guide_to_Medical_Cannabis:_DVLA_Rules,_Section_5A,_and_Staying_Legal

Legality isn’t an excuse for impairment. If you drive with medical cannabis, you must meet DVLA fitness standards and stay under the 2mcg/L THC limit. A medical defence helps, but your primary duty is ensuring you are fully safe behind the wheel.