Medical cannabis is legal, but driving isn't a free-for-all. Keep under the...

https://dlf-ne.org/can-i-drive-in-the-uk-if-i-have-a-medical-cannabis-prescription-the-reality-behind-the-wheel/

Medical cannabis is legal, but driving isn't a free-for-all. Keep under the 2μg/L THC limit and maintain DVLA fitness. A medical defence exists, but legality doesn't replace personal responsibility: if you’re impaired, stay off the road.