Lord Bernard Hogan-Howe investigates into whether Cannabis should be legalised in the UK. As part of his investigation he visits Colorado - one of the first states in the US to legalise - and sees first-hand how the cannabis business is booming, how the state is using its quarter-of-a-billion-dollar tax dividend and discovers that some strains of cannabis on sale are six times stronger than skunk. Tune in as he presents Dispatches - Cannabis: Time to End the Ban? Monday 22nd October at 8pm on Channel 4.