Cannabis will be legalised in the UK in the next five years, a former Tory minister chairing an influential parliamentary group on drug reform has predicted.

Crispin Blunt, who supports more liberal drug laws, said discussions about cannabis were "coming into the mainstream of politics".

Mr Blunt last year set up a lobbying firm funded by overseas cannabis corporations, which he on Tuesday revealed he had already discussed with Boris Johnson.

The group will formally launch on Thursday.

At the Cannabis Europa conference in London on Tuesday, Mr Blunt was asked how long he thought it would be before cannabis was legalised.

"Five years is the time I'm going to aim for," he said.

"I'm the first Conservative to be the co-chair of the All-Party Parliamentary Group on Drug Policy Reform, and it reflects the fact that this conversation is now coming into the mainstream of politics."