Medical cannabis patients often rely on the 2µg/L THC threshold and the...

https://evpowered.co.uk/feature/medical-cannabis-and-uk-driving-laws-what-ev-owners-must-know/

Medical cannabis patients often rely on the 2µg/L THC threshold and the ‘medical defence’ to stay legal behind the wheel. However, legality isn’t a blanket safety net. You must still declare your prescription to the DVLA regarding fitness to drive