Using prescribed cannabis as a driver requires caution. While a 2mcg/L THC...

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

Using prescribed cannabis as a driver requires caution. While a 2mcg/L THC medical defence exists, you must still meet DVLA fitness standards. Remember: legality doesn’t replace responsibility. If you’re impaired, you’re liable