Everyone loves a hero, and the media loves creating them. So it is hardly a surprise that Alastair Humphreys' five-year round-the-world bicycle odyssey has been largely portrayed as a charitable undertaking.

But after catching up with the Briton as he passed through Tokyo recently, it was soon apparent that he's not quite the knight on a shining bicycle that commentators love to wax lyrical over.

Following "a standard saving-the-world kind of gap year" spent teaching in South Africa, where he confesses to having contracted wanderlust, Humphreys, now 29, cycled from Pakistan to China during his first year at Edinburgh University.

"Then I spent the rest of my years at university working out how I could somehow not get a normal job, and get out of England," he said. "So I was saving up all the time, but I didn't know what for."

To many people, the thought of stepping off the career ladder for even a few months may be anathema. But Humphreys' philosophy centers on the most worthwhile way to use his life "rations" -- or "60 years till game over," as he puts it. So to him the trip is an apprenticeship for life, and the fact that he can "heroically" raise a bit of cash for charity along the way is a bonus.

"I didn't really give it huge amounts of thought in terms of 'Am I willing to allocate this much of my life to this project?' It was more a case of: 'I want to get out of England, I want to travel, I want to have adventures, I want to try and get into travel writing as a career.' So all those things added up into this huge project.

"I was a real angry young man at university. I'd been on this conveyor belt all my life -- prep school, school, university -- just gearing me up to get some fancy job in a bank in London and work every day until I retired. And then I'd play golf, and then I'd die. I think that's what was bothering me the most."

But now, after the loneliness and hardships of his current expedition -- 3 1/2 years of pot-noodle subsistence, cycling eight hours and between 100 to 160 km a day in temperatures ranging from minus 40 degrees in the icy wastes of Siberia, to 45 degrees in the deserts of Sudan -- a comfortable life seems a lot more attractive than it used to do.

Humphreys described his "lowest point of all" as when he reached Syria about three months into his trip. "That is quite a long time cycling," he said, "but when you look at a world map, England to Syria is a tiny distance compared with everything that was to come.

"I was in this hovel of a hotel, and I just lay on my bed and cried for about three days," he admitted. "It was awful, because I really just thought I'd got myself in so deep, but I had too much male pride and I couldn't bear to quit and go home and have all my friends laugh at me. I just felt so trapped."

After that, things could only look up -- and they almost immediately did. As he continued to pedal through Syria -- shortly after 9/11 -- he found, much to his relief, that he wasn't beset with flag-burning extremists.

"Before I crossed the border into Syria I was really scared about what would happen to me, but the people were great there and in Lebanon, Jordan and Sudan. They treated me really well, and knew there was no connection between me and George Bush," Humphreys said.

In a world where much selfless do-gooding is driven by opportunism or aspirations for self-promotion, Humphreys' frankness about his motivations for the expedition is refreshing. But while fundraising for the charity Hope and Homes for Children came second to the initial idea of the trip, its importance has greatly increased as Humphreys' journey has progressed -- especially, he said, after seeing their work in Sudan and South Africa.

"It was so inspiring to meet these kids who'd gone through so much madness in their short lives, and yet were still so smiley and happy. And there was I, this rich white kid on a five-year holiday, feeling so sorry for myself. It was really humbling to see them."

Only 10 years old but growing fast, Hope and Homes works with NGOs in 14 countries to provide a family and a future to young victims of war and disaster. The nature of the work varies from country to country: tracing the families of displaced children in Sudan; helping South Africa's AIDS orphans, many of whom end up heading households at age 13 or 14; and taking children out of eastern Europe's huge state-run orphanages and placing them in foster homes.

Humphreys may feel the weight of time heavy on his shoulders, but he admits he could hardly give up now having come so far. His determination is an uplifting example, and he says that he won't rest even when he has completed his epic trip.

"I definitely don't want to see this as my achievement for life. I want this to be a springboard. I don't want to be sitting in a bar in 50 years saying: 'I cycled around the world.' I definitely, definitely don't want to be doing that . . . though I probably will."

Oh well, even heroes have their Achilles' heel.