bushmaster pit viperHere's a jungle trial the pampered celebs on I'm A Celebrity . . . Get Me Out Of Here might want to try. Leave Ant and Dec behind and go to one of the most remote locations on earth, somewhere it would take a rescue team a good week to reach you - should you be able to contact them.
Then smash your satnav and throw away all your food apart from 2lb of salt. Now walk for two months, surviving on no more than your wits and what you can forage from the dried-out land and parched riverbeds. No takers? Thought not.
While the Z-listers of I'm A Celeb have been whining away in their cosy jungle camp, protected from the sun and rain by canopies the cameras do not show - with a medic nearby should one of the poor darlings break a fingernail - one man has been doing it for real.
Former British Army captain Ed Stafford, 33, is well on the way to becoming the first man in history to walk from the source of the Amazon in the mountains of Peru to its mouth in Brazil. And he's not doing it in the hope of achieving notoriety, nor is he being paid handsomely for his efforts. No, he's doing it out of a sense of adventure - for the sheer derring-do.
He is 612 days in - and looking to finish next August. If he achieves his aim, it will be a stupendous achievement, right up there with Hillary's ascent of Everest and the conquerors of the poles.
The challenges he faces are monumental. So monumental, in fact, that Arctic explorer Sir Ranulph Fiennes has written to Ed to warn him that the stage in front of him - the deep Brazilian jungle - will be 'difficult'. You can take it that this is something of an understatement, given that it comes from a man who once sawed off his own fingers after they became frostbitten.
His average day would kill most people. Up at dawn, he walks for around eight hours, until 3pm. At this stage of the journey he will be lucky to have covered 7km in that time. This is jungle, real jungle - and you pay for every step with willsapping swings of the machete.
It's like clearing the thickest hedge you could imagine for a whole working day. Only this hedge is filled with razor grass - which is pretty much as the name implies, grass that will cut exposed flesh to ribbons - huge thorns and spines on trees sharp enough to go straight through a carelessly placed hand, deadly snakes, poisonous
Once he makes camp, he gathers firewood and - if there's water - he washes. Sometimes he might catch a few spiny piranhas to eat. But if he doesn't, he goes hungry. If you offered him one of the celebs' witchetty grubs, he'd regard it as a rare treat.
Has he been near death? Regularly. Sometimes daily. Only last week he was cutting his way through the jungle when he saw a movement. It was a deadly pit viper, ready to strike. Ed backed off. Luckily, so did the snake.
At dusk, he climbs into a hammock surrounded by mosquito nets. It's a sanctuary where he can read, write and try to sleep, although he's compelled to take sleeping pills, despite his exhaustion; the deafening noise of the jungle, the buzzing insects and the cries of monkeys, birds and animals - as well as the sauna-like temperatures - mean he would have no hope of rest otherwise.
I have a great appreciation of what Ed is facing, as last year I met him for part of his walk through the Peruvian stretch of the jungle.
In my time with him I was nearly swept away by a raging river, caught an all-over rash that made me look as though I'd been grilled, had one pair of shoes disintegrate on my feet, narrowly avoided being bitten by a snake, even more narrowly avoided sitting on a Poison Dart Frog, got lost, was accused by suspicious locals of trying to steal children's eyes and, oh yes, was taken hostage by 20 shotgunwielding villagers.
I also reached the point of physical collapse and my left knee has never been the same since. How long was I with Ed in the jungle? Three days. And that was the easy bit.
He and his guides are the fittest men I've ever met. I thought I was no slouch until I walked with them. I exercise hard three times a week and walk an average of 15 miles on a Saturday with the dog on the Sussex Downs.
The chief's reception was far from welcoming and he threatened to throw us into the jungle in nothing more than the clothes we stood up in. Which was when the armed men appeared.
At the end of the hardest exercise I'd ever done in my life - 12 hours of crawling, climbing and chasing through the sodden jungle - here I was bargaining in my appalling Spanish for my life. Or rather, Ed was bargaining for me - in his rather better version of the language.
After a lot of discussion, we were marched to a shack and told not to move. Our fate would be decided by morning.
Luckily, Ed took control of the situation and approached the gunmen with some packets of cigarettes. After 20 minutes chatting to him - without the benefit of the chief's intervention - they were laughing and joking like old friends.
Ed then explained how sometimes the locals put on an act of aggression as a bargaining position to get money out of you. How do you know when they're serious, though?
'You don't,' he said with a shrug. He obviously made some impression because the next morning the chief made himself scarce while the rest of the village waved us away.
Ed seems a natural-born leader - and the guides told me they thought he was a very tough guy. That, from people raised in unimaginable poverty, who face more challenges in a day than most of us do in a lifetime, is some compliment. One of them has stayed with him all the way from Peru into Brazil - and is still travelling with him now.
His satnav is broken and even if he had enough money for guides, he wouldn't be able to get them anyway for this section of his expedition.
The locals are too scared of jaguars
to go into the jungle. The big cats find pickings lean in the dry season and a juicy explorer would be a welcome addition to their diet. Ed is, of course, unarmed. A gun might give protection from the wildlife, but it would guarantee hostility from the people.
'I am scared of the next part,' he tells me via satellite link. 'We've already been on the point of collapse through malnutrition and dehydration- - and it looks like we're in for much more of the same.'
When Ed says he's scared, you know its something worth being scared about. After all, this is someone who has worked as a security consultant in Afghanistan, where he was once detailed to guard a polling station.
Unfortunately, the militia weren't too keen on the election taking place and the station was overrun by 500 screaming tribesmen firing assault rifles into the air.
the river floods to miles wide. He will come into contact with remote tribes who are living the same way they did when Portuguese colonists arrived.
In Peru he encountered people who had never seen a white man. Here he may meet those who have never even heard of one. It's Ed and his guide with that bag of salt (for preserving fish) versus the most hostile territory on earth.
His only back-up is his friends and family. His mother is looking to sell her house to support him. That's how much she believes in what he's doing.
The trip is a pure challenge. There's no artificial degree of difficulty to it; he's not trying to be the first man up Everest in a gorilla suit playing a banjo - he's trying to walk the Amazon, the cauldron of heat, disease and hostility.
It's something that would have appealed to the Victorians in th
e great age of British exploration; if Ed comes out alive he will deserve a place alongside Scott, Livingstone and Shackleton - something he's very proud of.'It's good to stand in the long and distinguished line of British nutters who think its clever to put themselves through hell to achieve something that no one else ever has,' he says.
Will he succeed? Probably. After all, he's proved that running out of funds won't stop him, and physical hardship won't beat him.
If the Amazon wants to remain unconquered then it's going to have to kill Ed Stafford first - something it seems more than prepared to try.
