When I started writing my book, two months after returning from the Amazon, I was already blocking out the hard times and selectively remembering an excitement-packed two-year adventure. But when I started to read the journals that I'd written in my hammock each night, I realised that I'd been pretty miserable for large parts of the journey.
My mission was to travel the length of the Amazon, from source to mouth. At one point, in Peru, I was in a totally closed off area of Amerindians. Few white people went in by river, and certainly none on foot – as I was with my guide Cho, a forestry worker who walked with me for 24 of the 28 months of my journey.
Some indigenous tribes in this part of the world consider themselves autonomous – they don't follow the laws of Peru. As we travelled, we used a high-frequency radio network to talk to the tribes as we approached, so we could ask their permission to come through. In this area, a tribe called Pensilvania said over the radio that they would kill any white people who came by. We were worried, but had no choice but to pass through this area. To try to avoid them, Cho and I paddled out to a shingle island in the middle of the river, then walked down it for two kilometres, hoping to avoid the Pensilvania. When we reached the downstream end of the island and were about to get back into our inflatable rafts Cho said, "Ed – look behind you". I turned and saw five canoes paddling up to us. The men were armed with bows and arrows or shotguns, the women with machetes.
I thought, this is it: we are going to be killed.
Luckily they weren't Pensilvania; they were a different tribe. But they were furious that we were trying to pass without permission and escorted us back to their community and made us take all our stuff out of our bags.
In general the tribes didn't want people walking through their land. This tribe was no different. They hadn't issued a threat, but they hadn't given us permission to pass either. They said they would only let us through if we hired the chief and his brother as guides. We pretended to be really put out by this, that it would be a huge inconvenience, but actually we were thrilled. We really needed local guides to help with introductions at subsequent communities.
Alfonso and Andreas walked for 47 days with us, and became really good mates. We could all speak enough Spanish to communicate. Cho and I were travelling with a pack raft – a small one-person inflatable kayak – each. With the extra company we had to double up, sitting in the rafts end to end. It felt like sharing a bath.
I was sharing a pack raft with Andreas and I accidentally dropped our last machete – which we really needed – into the water. Though not a disaster, this would inconvenience us greatly – but Andreas, the chief, and I had become good friends by this point and we just shared a guilty schoolboy grin. They ended up being really lovely, loyal friends: the same people that came out to defend their land and who were, I am sure, ready to kill us had we been aggressors. At the end of the trip we paid them, and were a bit worried that, like other tribesmen we had met, they would spend it all on alcohol, but these guys bought an outboard motor to take back to their community.
None of the tribes we met found what we were doing strange: they all enjoyed walking, and understood why we would want to go out and enjoy the forest, and write a book about it.
Even these really closed off communities have generators and watch TV. Theirs is a bizarre little world: it seems totally isolated, but then they're watching Brazilian soap operas set in Rio.
Many communities in Peru have suffered atrocities over the years – whole generations of men wiped out, and women violated. In Brazil we had less trouble: there is more money there, and more education. There were fewer communities, and we could go two or three weeks without seeing anyone. The latter half of the trip was more like that, and nicer for it. We had fewer problems – except for running out of food.
At one point we had been walking for 30 days through places with no human habitation, and I decided that we were eight more days from a community that was marked on our map. We worked out that we had just 450 calories a day to live on, so we walked for eight days, and on the last day there was nothing there. We had no food, we were in the middle of the jungle, our GPS had broken and we only had a compass and a map that was 1: 4m to navigate through Brazil. (That means 1mm was 4km – military maps are 1: 100,000.) We were really out on a limb. But the next day Cho found a tortoise. We'd made it a policy not to hunt, but that tortoise jerky saved us.
With food low and kit breaking, we had to increasingly live off our wits to survive. It became the part of the expedition that was the most memorable. Before I set off, everyone told me the challenge was impossible, but I was adamant it wasn't.
Although the real reason I came up with the idea was to have a big adventure, one of the most rewarding aspects of it was the relationship we had with schools around the world. I was writing a blog for the Prince's Rainforest Project for School's site and kids would send us questions. I would answer them by video and then upload the films. Teachers used it to spice up their lessons and bring the Amazon to life. Sometimes we were uploading films about the fact that we had run out of food before we managed to find any.
Another great thing to come out of the trip was my relationship with Cho. We walked for two years together and became good friends. He has since come back to the UK with me, and it would have been weird to leave him after showing him what the western world has to offer.
He applied for a visa to stay here but it's very hard for Peruvians to get one, and he was turned down. But at my book launch at the Royal Geographic Society, I spoke to Michael Palin about our trip, and he wrote to the ambassador on our behalf – and the visa decision was reversed. So now Cho is staying with my mum, who lives in Leicester, and has been learning English. He's not sure what he wants out of his future but he's keen to see more of the world. He's become a very loyal friend and I owe him a lot.
As told to Gemma Bowes