This year’s edition will constitute a 14th successive stint in the jungle, and its international appeal shows no sign of slowing down any time soon.

A smash hit in the UK as well as France, Germany, Hungary, India, The Netherlands, The US and Sweden, there is even talk of a specifically Aussie version coming out next year with contestants jungled up in Africa, rather than good old Oz.

Over that time the format has – unusually for TV – remained remarkably consistent. Twelve disparate (and sometimes desperate) celebrities are routinely humiliated as they show themselves prepared to do almost anything in order to win the ‘admiration’ of the audience.

One of the best kept secrets of the show is how much contestants get paid for either being bitten by different critters or getting their own teeth into the less appealing bits of some bigger beasts: Crocodile anus, kangaroo testicles and those old favourites mealy worms and witchety grubs are just a sample of the sadistic smorgasbord on offer.

As a formula that works there is every reason to stick with it. “I’m a Celebrity” is not just a hugely successful TV format. It’s commercial span is an object lesson to anyone with an entrepreneurial bone in their body as to how to make the most of what you’ve got.

Since 2006 the UK show’s tie in with supermarket Iceland is one of the most long-lasting and successful TV sponsorships around. Iceland routinely use celebs who appear in the show in their own branded ads, and they combine this with ‘I’m a Celebrity’ branded products and in-store merchandising.

Online the buzz which the format has sustained has been picked up by the likes of 32Red casinos who have produced a game themes around the show as a way to encourage punters to visit the 32Red online casino.

The 32Red is one of the show’s spin offs that is capable of transcending national boundaries, but a key aspect of the show’s global success is the way it is able to tap in to different international audiences. “I’m a Celebrity” isn’t just a TV format any more: It is a global industry.

And at the heart of that industry are the people who are prepared to expose their fears, phobias and bad habits to the watching millions. Whatever you think of the format, or its naked commercial thrust, over the years there have been some truly memorable televisual treats.

Gillian McKeith’s faux faint when she was condemned to yet another Bush Tucker Trial in 2010 takes some beating. At that point we realised the full depths that the infamous ‘poo lady’ was prepared to plumb. Who did she think she was fooling?

Nearly as unbelievable was the hysterical gurning produced by super posh former Royal Butler Paul Burrell in 2004 when confronted with the so-called hell-hole challenge. ‘I can’t feel the star’ he whimpered as he pushed his hand into a hole full of spiders. You had to see it to believe it.

Burrell’s not the only notable wimp down the years – Dean Gaffney’s squealing in 2006 was  something to behold, as was Sinitta’s inability to deal with anything that fell below the level of five star room service in 2011 – what on earth did she think she was letting herself in for?

The real horrors though are not so much the challenges – gory and indigestible as they may be. What is really shocking is the occasional insight into the showbiz mentality that gets exposed. Peter Andre’s carefully plotted 2003 song-writing scene was maybe not some of his finest acting. Following what was possibly the creepiest manipulation of the medium since the Cold War, Andre’s “Insania”went on to reach number 3 in the UK singles chart. And of course he copped for Katie “Jordan” Price into the bargain.

The best bits though, invariably involve people with something more about them than just a hungry career ambition. Former punk John Lyden’s encounter with a bunch of grumpy ostriches takes some beating, as does the no-nonsense guts and good humoured determination shown by Carol Thatcher in 2005 – happily driving a car off a ravine crossing seemingly without a care in the world. Shaun Ryder’s angry reaction being bitten by a snake in series ten was a classic of machismo, as – in its way – was Fatima Whitbread’s nose bug in 2011.

Whoever it is that enters the jungle this year – and speculation is rife with talk of Olympians and Hollywood Alisters – we can be guaranteed that there will be something memorable to see. It may be kitsch and it may be stagey and just a little bit distasteful, but it remains one of the most compelling and successful TV formats ever. And in the process it remains a huge commercial success story in its own right.