Medical cannabis users have a statutory defence, but don't get complacent. You...

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

Medical cannabis users have a statutory defence, but don't get complacent. You must respect the 2μg/L THC limit and notify the DVLA of your fitness to drive. Remember, legal status isn't impairment immunity; your safety duty stays firmly with you.