Late last year, the writer, polemicist and fierce proponent of the US-led invasion of Iraq Christopher Hitchens attempted, in a piece for the online magazine Slate, to draw a distinction between what he called techniques of "extreme interrogation" and "outright torture". From this, his foes inferred that since it was Hitchens' belief that America did not stoop to the latter, the practice of waterboarding - known to be perpetrated by US forces against certain "high-value clients" in Iraq and elsewhere - must fall under the former heading. Enraged by what they saw as an exercise in elegant but offensive sophistry, some of the writer's critics suggested that Hitchens give waterboarding (which may sound like some kind of fun aquatic pastime, but is probably best summarised as enforced partial drowning) a whirl, just to see what it was like. Did the experience feel like torture?

 

And amazingly, he has done just that. In August's edition of Vanity Fair, you can read all about it, and see more photographs of the "wheezing, paunchy, 59-year-old scribbler", his head hooded, being subjected to this most terrifying of ordeals by veterans of the US Special Forces. A video is due to be posted soon at vf.com, though that may be a bit too much to bear.

So what did it feel like? Hitchens recounts how he was lashed tightly to a sloping board, then, "on top of the hood, three layers of enveloping towel were added. In this pregnant darkness, head downward, I waited until I abruptly felt a slow cascade of water going up my nose ... I held my breath for a while and then had to exhale and - as you might expect - inhale in turn." That, he says, "brought the damp cloths tight against my nostrils, as if a huge, wet paw had been suddenly and annihilatingly clamped over my face. Unable to determine whether I was breathing in or out, flooded more with sheer panic than with water, I triggered the pre-arranged signal" and felt the "unbelievable relief" of being pulled upright.

The "official lie" about waterboarding, Hitchens says, is that it "simulates the feeling of drowning". In fact, "you are drowning - or rather, being drowned".

He rehearses the intellectual arguments, both for ("It's nothing compared to what they do to us") and against ("It opens a door that can't be closed"). But the Hitch's thoroughly empirical conclusion is simple. As Vanity Fair's title puts it: "Believe me, it's torture."