Medical cannabis is legal, but driving remains a minefield. With a 2μg/L THC...

https://wiki-triod.win/index.php/What_counts_as_being_impaired_if_I_am_on_prescribed_cannabis%3F

Medical cannabis is legal, but driving remains a minefield. With a 2μg/L THC limit, a prescription offers a potential medical defence, yet it doesn’t bypass DVLA fitness-to-drive requirements