Channel 4 News presenter Jon Snow has told how he got stoned on skunk – strictly for professional purposes of course – and ended up more terrified than he had ever been reporting from a war zone.

Snow, whose previous experience of drugs was being “passed the odd spliff of cannabis” in the distant past (although he did accidentally drive down the M40 on acid), said he felt “utterly bereft” after inhaling the first of “two huge balloons of the stuff” for Channel 4’s Drugs Live programme in March.

Jon Snow (@jonsnowC4) Stoned on Skunk: I felt my soul had been wrenched out of my body http://t.co/JWznuvoxol pic.twitter.com/grmk0Gfm1x

“I felt as if my soul had been wrenched from my body,” he said.

“There was no one in my world. I felt I had lost all control and had only the vaguest awareness of who I was and what on earth I was doing.

“I cascaded into a very, very, dark place, the darkest mental place I have ever been. I was frightened, paranoid, and felt physically and mentally wrapped in a dense blanket of fog. I lost all sense that I was being filmed by Channel 4.”

Jon Snow: ‘I never want to be subjected to that again’

Worse was to come when it turned out Snow, who took part in the test after reports that 25% of all psychosis treated in Britain is associated with smoking skunk, was too tall for the MRI scanner which was going to monitor the effects of the drugs on his brain.

“The mask over my head kept catching the top of the inside once I’m pushed in,” he recalled. “The terror in me kept rising, my panic chasing hard behind. When you see the film, you can hear this distant voice wailing ‘I can’t stay in here … let me out!’

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“I’ve worked in war zones, but I’ve never been as overwhelmingly frightened as I was right then – and as I emerge from the scanner you see me blearily sitting up and hugging young Dr Rebecca for my dear life, as if she was my mother.”

Still, the experience proved not to be entirely negative.

“It took me four hours to come down,” Snow wrote on his Channel 4 blog.

“Just toward the end, I felt a sense of euphoria and expressed it by drawing a pastoral scene on an old box that was lying around in the lab. I drew trees, a fence, a river, and a couple of people – perhaps the very people, trees, and water, that I had felt so deprived of whilst stoned.”