Get me in there!

She said it was 'X-rated entertainment with all the appeal of last night's chicken pie'. So what the hell is she doing on 'I'm a Celebrity...'? Janet Street-Porter explains all

Let's get one thing straight. I have changed my mind several times over the last decade - about Mr Blair, eating bread, getting married, and owning a flashy car. But this week sees my biggest U-turn yet - I've decided to participate in the television show that I once described as "brain-rotting". By this Saturday evening, I shall be trapped in the tropical rainforest somewhere in deepest Queensland, slapping on the mosquito repellent and trying not to strangle Paul Burrell.

Let's get one thing straight. I have changed my mind several times over the last decade - about Mr Blair, eating bread, getting married, and owning a flashy car. But this week sees my biggest U-turn yet - I've decided to participate in the television show that I once described as "brain-rotting". By this Saturday evening, I shall be trapped in the tropical rainforest somewhere in deepest Queensland, slapping on the mosquito repellent and trying not to strangle Paul Burrell.

In May 2003, I was so repulsed by the sight of Daniella Westbrook bawling her eyes out on I'm a Celebrity... Get Me Out of Here! that I wrote, "As for calling them celebrities, I've seen more talent in the rare- sheep class of the Upper Nidderdale agricultural show. Women with bad bleach jobs, rebuilt faces and overplucked brows. Men with paunches clutching at cigarettes as if they were life-support machines".

In my one-woman show, I get a load of laughs when I read out all the ghastly reality TV show offers I've turned down over the last two years, from Gender Swap to Celebrity Detox to How Clean is Your House?. I wouldn't have a rubber tube shoved up my bottom and the contents sluiced out in the privacy of my own home, let alone live on television in the living rooms of eight million viewers. But when my friend John Lydon took up the challenge of I'm a Celebrity... last January, decamping to the jungle with Jennie Bond, Jordan, and Mike Read, I was incredulous. I wrote: "I am prepared to grit my teeth and tolerate the unthinkable - hours of babbling from Ant and Dec, the two most anodyne men in popular culture - in order to get my fill of what promises to be one of the best forms of legal combat left." To me, John Lydon is more devastating in the flesh than any weapon of mass destruction. Then, to my horror, just as the nation gradually warmed to my point of view, our man got up and walked. All over Britain you could hear the sighs of disappointment.

Why John Lydon decided to evict himself out of a show that he probably would have won remains a mystery. It seems that he genuinely didn't understand the impact that he was having on viewers. We were left with the nauseating sight of the washed-up pop star Peter Andre wooing the pneumatic Jordan, and the former Royal expert Jennie Bond pottering about with her hair in girlie bunches, popping the odd stick insect in her mouth as final confirmation that she'd lost all reasoning. At that moment, I decided that I would take up the challenge that John had flunked.

I had been approached before, but this time I would go for it. I wanted to see if I could survive two weeks of intense physical and mental torture - not swatting mossies, flicking away snakes, defecating in a hole in the ground - all stuff I've dealt with many times while hiking around the world.

No, I wanted to see whether I could deal with a torture far, far worse - listening to Paul Burrell wittering on about recipes that Diana loved, or perhaps hearing Brian Harvey playing a few bars from a song with which he's hoping to revive his career. Then there's the prospect of Joe Pasquale telling endless jokes in a squeaky voice, and Sophie what's-her-name twittering about in seductive smalls, re-enacting her latest underwear ad.

When I turned 55, I decided to rethink my life. I would Age With Attitude. I'm not going to be one of those greying feeble females who fade into the background and wait to claim their pension, letting a younger generation take centre stage. Bugger that! First, I devised a stage show and took to the boards at the Edinburgh Festival. The show was a sell-out, and I followed it up with a book about my childhood. I told the world that my mother was a bitch, and hundreds of women wrote to thank me for tackling a taboo subject. Then I decided to set myself a series of personal challenges in order to slow down the onset of crabby old age, spending a week in a remote village outside Nefyn and being intensively taught Welsh.

In March, I visited a Buddhist centre in the Blue Mountains for a silent retreat. In September, I spent eight days walking through the Australian desert, and last month, I agreed to be trained and filmed for two weeks working as a primary-school teacher on the outskirts of Cambridge. All have been tough but rewarding experiences. I'm a Celebrity... represents another kind of challenge - will I be able to curb my naturally acid tongue, restrain my bossy domineering personality, and try to live in close proximity to people whom I would normally cross the road to avoid?

Doing without mundane creature comforts such as skin cream, lipstick, a mobile phone or cotton sheets won't be a problem. The mental challenges are far more taxing. I am emptying my mind ready to allow it to refocus on a different, more mundane wavelength, where chat is about whom you "miss" - a completely alien concept to self-centred me. Physical challenges, eating maggots and swimming with crocodiles will be light relief. Being nice presents far more of a problem than the possibility of having a limb munched on by reptiles, or something that drops out of a tree. There are some other caveats. You won't be seeing me in skimpy shorts as I have rejected the women's clothing on offer in favour of the baggier male attire - far more suitable for my statuesque vital statistics. I also give you my word that I will not sport any of the following: a thong, a bikini, beads or body adornments made from twigs, stones or charcoal. I won't be braiding my hair in corn rows or snogging anything human under cover of darkness. I'd rather sleep with a cockroach than any of my teammates.

Climbing Kilimanjaro a few years ago, I perfected the art of minimal packing and recycling, turning my M&S Bridget Jones-style white cotton knickers into flannels, and finally dusters to clean my tent after use. I drank out of old yoghurt cartons and peed in them at night. I cut up black plastic bin bags and turned them into waterproof jackets and rucksack covers - who knows, I might morph into such a nice, new Janet that I do the same for Huggy Bear or Nancy Sorrell. But don't hold your breath.

Finally, my luxury item isn't a guitar, a camera or tweezers. I've been allowed to take a Moleskine notebook and pen. For years, I have kept a diary wherever I have travelled, from Papua New Guinea to Chile, New Zealand to Tasmania, and this latest escapade is to be chronicled, in all its joys and miseries, within those stiff covers. You might think that you're seeing everything unfold on your screens at home, but just wait till you read what I really thought afterwards!

Finally, I'm sick of people asking me how long I'll last before I bail out - they clearly misunderstand my ruthless nature. I'm in this thing to win - so vote for me and strike a blow for crumblie power! I'm implant-free, fit and fiftysomething, looking forward to the challenge ahead.

Showbiz publicist Mark Borkowski's strategy for survival in the reality rainforest

So Janet is off to the jungle, swapping the cool of Clerkenwell for torpid Kookaburra. Over there, in the steaming hothouse of reality TV an intrinsic part of the 'I'm A Celebrity' format is about how you react to authority and rules. One only has to look at past winners and the harsh environments in which they originally thrived to identify the character traits most likely to bring triumph.

Look Vulnerable: This tactic was never better employed than by Tony Blackburn. There's no more Machiavellian regime imaginable than an oldies radio station, when at any moment a reckless playlist change can result in the surprise substitution of Cliff Richard for Barry Manilow, and the loss of one's place in the weather forecast. That's why Tony emerged so triumphantly: he's the real vulnerable deal, and when the red light went on, he even started to look cool. Well after a fashion..

Look like you don't care: You weren't taken in, were you, by Phil Tufnell's lounging around, looking as though he couldn't give a damn? That's what he appeared to do in the outfield on his 42 appearances in the England cricket team, when what he was really doing was planning the next 120 test wickets and piss up after. If your in it, you want to win it.

Stay true to yourself, and believe in yourself: Janet's fundamental refusal to bow and scrape to anyone will serve her well against the grovelling Paul Burrell, whom I'm sure she's capable of reducing to tears with a single sneer.

Create an unforgettable TV moment by completely losing your rag: Janet's better prepared than anyone for a show like this. 'Celebrity' is about great TV, something she knows intimately and she needs to deliver.

Don't diss the programme-makers: It's the editors who have the power to really influence who will win. They gave Uri Geller and Kerry MacFadden enough rope to see whether they hanged themselves or lassooed the love of the nation. The fabulous eccentricity of the Street-Porter brand should surge to the fore.

Don't forget your USP: Is she there to bring in the punk ethic in the same way Johnny Rotten did ? Is she there to excite an increasingly frail group of males who lusted after her in the 1970s? Or is she going all the way to Oz to eat kangaroo's testes simply to broaden her social horizons? Let's hope she plays to win.

'I'm a Celebrity... Get Me Out of Here!' starts on Sunday on ITV at 9pm