Bill Turnbull gets high on camera in bid to cure prostate cancer

In Bill Turnbull: Staying Alive — an emotional documentary that's at times both heartbreaking and hilarious — the TV presenter tries different products derived from cannabis (still illegal in the UK), with amusing results. In the segment, Turnbull smokes cannabis on camera, before the film skips forward to the presenter laughing hysterically and pretending to choke the director, who says: "Bill, you seem to be laughing a lot."

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"This is really unfair. Unfair. No, no, not laughing at all. Right, behave," Turnbull replies, before attempting to deliver a line to camera about what he's just tried. "I cannot compose a sentence. I just can't do it," he says.

Speaking at a press Q&A hosted by Channel 4's Krishnan Guru-Murthy, Turnbull joked that the cannabis made him "giggle" and left him "wanting to throttle Ashley the director," but added that attitudes towards the drug need to change.

"I do think we need to have a proper conversation about the use of cannabis for medicinal purposes. Because it’s legal to a greater or lesser extent for medicinal purposes in I think more than 20 countries now. In quite intelligent, advanced countries, and I think we should be one of them," he said.

"We have something that’s been used for thousands of years for medicinal purposes, only been illegal for about 100 years [it was prohibited in the UK in 1928]. And we need to start having conversations about how can we usefully get the best out of what could be very beneficial to us, without causing damage to other people. I’m not talking about recreational use, I’m simply talking about it for medicinal reasons," he added.

In March last year Bill Turnbull spoke for the first time about his incurable prostate cancer diagnosis in a Radio Times interview with friend and former BBC Breakfast colleague Sian Williams.

Bill Turnbull: Staying Alive airs Thursday 24th October at 10pm on Channel 4