The iceman cometh: Vincent Graff emerges from the Kriotherapy Chamber at Champneys Spa in Tring

The words on the document in front of me are unequivocal: this may provoke heart attacks or strokes.

Now, I’ve signed plenty of legal documents in my time — haven’t we all? — but never before have I agreed to take part in an activity that warns of this kind of lethal outcome.

But the friendly woman waving the consent form under my nose is insisting I sign before I go any further. And, of course, I do. like you always do.

As I scribble on the dotted line, a small shiver goes down my spine. Never could a reaction be more appropriate. For whatever happens, I know one thing for sure about today: There’ll be a lot more shivering.

In a few moments, I will be stepping inside a chamber that is colder than the coldest day on the coldest place on earth.

The kriotherapy room at Champneys health resort near Tring, Hertfordshire, is kept at a staggering minus 130C. The lowest naturally-occurring temperature ever recorded on the planet was a day in July 1983, when a ?thermometer at the Vostok research station in Antarctica measured minus 89C.

I must be mad. but I’ve come on a good recommendation. As the Mail revealed last week, Tony Blair was here on the last ?Saturday in January, hours before flying back to Jerusalem to resume his duties as Middle East envoy.

‘He’s been here half-a-dozen times, I ?suppose,’ confirms general manager Patrick Lemaigre. ‘mrs Blair has been here more. I think she must have convinced him.’why does he come? ‘without going into too much detail,’ says Patrick, ‘he’s obviously under a lot of pressure and I think it just helps him feel better.’

There are huge claims for kriotherapy (often called cryotherapy). Advocates claim it can assist with everything from sports injuries to psoriasis to depression and ‘general fatigue’. It is also used by some ?sufferers of multiple sclerosis who feel it lessens their symptoms.

Patrick points out optimistically: ‘It can even reduce cellulite.’ Certainly, Tony and Cherie are not the only high-profile advocates of kriotherapy. The walls of the treatment area are lined with signed photographs of previous satisfied customers. Here’s the Tottenham Hotspur squad. a few inches along, isn’t that Pamela Anderson? And what’s this — the rock legend Alice Cooper emerging from the chamber in full black eye make-up . . .

So, what’s the theory behind the therapy?

very simple, explains Renata Zejer, the enthusiastic Polish woman who runs the chamber. She’s been working in ?kriotherapy for 12 years, the first nine in her home country, where the treatment is so mainstream it is available on the local equivalent of the NHS.

Walking into the chamber is basically the opposite of going into a sauna, she explains. ‘when the cold air touches your skin, a message goes straight to the brain: “It’s ?dangerous to be here.” so your body goes into protective mode.’

Blood is diverted away from your extremities to the central organs of the body. then, when you leave, the process goes into reverse: the blood supply to the peripheries increases up to four times the normal volume. meanwhile, the brain is stimulated to release seratonin, the ‘feel-good’ hormone, and endorphins, ‘leaving you feeling really energised’.

Whoosh: inside the chamber the temperature is -130C. Icicles form inside our man’s nose and he wonders whether he will last the full three minutes

It’s not enough to quell my nerves. I’ve heard of people demanding to be let out of the kriotherapy chamber after a few seconds. ‘you will only be in there for three minutes,’ she tells me.

Will I be allowed out at any time? ‘of course.’will it hurt? ‘no, it’ll feel chilly. but no pain.’just chilly? at minus 130C?

Renata may be Polish, but she is better at understatement than the English.The worst that is likely to happen is that ‘some people feel a bit dizzy. but if that happens all you’ve got to do is relax inside’. The trick is to keep moving, but not too frantically. And I won’t be thrown into minus 130C from a standing start. ‘you go in the acclimatisation chamber for 30 seconds first.’

And what temperature is that? ‘minus 60.’ Which is still colder than any natural ?temperature ever recorded anywhere in Europe. (A home freezer is typically minus 18C.)

But the good news is, I get to wear a special outfit. I put on two pairs of fluffy cotton shorts, two pairs of gloves, two pairs of ski socks that reach up my thigh, a thick hair-band to protect my ears, a surgical-looking mask over my mouth and nose, bandages over my lower arms and legs, and a pair of white wooden clogs.

I also wear an optional T-shirt, because I am a bit of a wimp. (But no more so than rock hardman Alice Cooper, who wore one for his treatment.)

Big fan: Cherie Blair has visited the spa ‘many times’. Other visitors include Pamela Anderson and the Tottenham Hotspur squad

The outfit will protect my extremities (‘frost-nip has been reported and frostbite is possible,’ says the legal document) while letting me get cold enough for the therapy to work.

Now, at last, it’s time for the three minutes of truth. Renata flings open the bulky door to the antechamber and a huge rush of dry ice escapes. ‘Walk in slowly, it’ll be very slippery,’ she says, following me in.

The cold hits me so suddenly my instant response is pure Anglo Saxon at the top of my voice. ‘Sorry about that,’ I say.

‘Don’t worry. Lots of people swear at me,’ she says. my body has turned rigid. not because it’s frozen solid, but because I’m anxious.

‘Remember,’ says Renata. ‘Relax. And keep moving.’ she orders me to march round in a circle, without stopping. One imagines this is the sort of instruction issued by jailers on death row to their inmates.

I’m obviously very cold, but I’m alert enough to look around as I march. not much to see. The walls are lined with plank s of light wood. The floor is concrete. Renata keeps me engaged in conversation so I don’t lose my nerve. (Perhaps that’s why Cherie Blair is said to sing always Look On The Bright side of Life in here.)

Renata opens a connecting door. Another whoosh. You’d think your body might not feel the difference between extremely, very cold and colder-than-anywhere-on-earth cold. but it does. ‘keep on moving,’ says Renata.

There’s music playing — ‘It’s Chopin, I think,’ says Renata — but it’s not doing a very good job distracting me. my feet begin to ache from the cold and, about 90 seconds in, I’m feeling very uncomfortable.

Icicles have formed in my nose. Renata fiddles with my face mask to prevent further ones. every time I speak my breath literally freezes in front of my face, obscuring my view.

Something in common: both Alice Cooper (left) and Tony Blair (right) enjoy the benefits of kriotherapy, which is said to boost the release of seratonin

Yet get this. inside, this chamber does not feel like the coldest place I’ve ever encountered (though of course it is). I’ve felt more uncomfortable when I’ve been hungry in the driving wind of an icy winter’s day.Is that partly down to the fact that I know the whole experience will come to an end after three minutes?

Perhaps. not that I want to pretend this is easy — it’s not. about a minute before I’m due for release, I get a sudden attack of doubt. will I last till the end? ‘Fold your arms in front of your chest,’ says Renata, adopting something like the crash position on an aircraft. this makes a surprising difference to my level of comfort.

It’s the last few seconds that are the hardest. she counts down: Ten, nine, eight . . . at the crucial moment, an alarm sounds and Renata flings the jail door open. Another huge release of dry ice, and out we both climb.

I feel very proud of myself. I’m told it’s 20C in the main room, but it feels like I’m ?sizzling under the Caribbean sun. Renata whips off my gloves, clogs and bandages.I touch the skin on my right arm. this is the creepiest moment of the day. For about a minute or so, it is firm and fleshy but stone cold. The ?feeling has gone. It’s like touching the body of a stranger. a dead stranger.

I’ve also turned goose-?pimply and red. my veins are bulging and blue. this, says Renata, is brilliant news. The blood is rushing to my extremities, just as it should be.And this is where the magic starts. It feels like I am walking on air. this is an endorphin rush far better than anything I’ve enjoyed after a gym ?session. I’m gabbling away, full of energy, full of enthusiasm. Loving life.

I like this feeling. I’d like to come back tomorrow, please. And here’s the odd thing. The mellow, positive feeling is still with me more than 24 hours later. I’ve no idea if I’m the victim of a huge placebo-effect, but I don’t think I am.

I’m never going to sign up for Cherie Blair’s mumbo-jumbo ‘birthing’ mud baths or her bio-electric shield pendants, but I’m really rather taken with kriotherapy. I’ve even managed to put the frightening legal warning to one side. Ignoring the advice of a lawyer? now, that’s something that Tony Blair would never do . . .