Round-the-world mountain biker Ken Roberts celebrated his 500th day in the saddle on Saturday January 15 – and in that time he’s passed through 14 countries, paid three bribes and been unlawfully detained in Kazakhstan.

Ken set off from Somerset on his purpose-built Thorn eXp expedition touring bicycle, called Emma, in September 2009, aiming to raise £45,000 for The Outward Bound Trust, an educational charity which helps children and young people realise their potential.

Since his departure he has cycled through Europe and Asia – shivering his way through -20c in Bulgaria and baking in 40c in the Gobi Desert – and has just set out from Cairns, Australia, looking to carve a path through flood-hit Queensland.

Ken’s journey can be followed on his website – www.acrosscontinents.org – and below is an extract from his diary, when he picked up an unexpected local supporter in the Shaanxi Provence of China.

An extract from Ken’s diary in China

“I’d been joined by a young chap mid-afternoon the previous day. Not sought his company, but, equally, was powerless to prevent him from accompanying me. Pleasant enough, but I knew more Mandarin than he did English. At first I thought he might follow me for a few miles. But he persisted. Into the town of Shangnan. Attempts to shake him off were fruitless.

I didn’t feel in the least bit threatened by his presence. But I was very uneasy about the situation. For one thing, I was uncertain of his age. Late teens perhaps. But who was he? Probably lived with his parents. Did they know where he was? I’d not seen a mobile phone. I feared he might have simply decided to embark on a bit of an adventure, accompanying me east. But I neither wanted a companion, nor did I wish to be party to someone’s impulsive, impetuous behaviour. No matter how well intentioned.

So I kept my distance as best I could. Strictly a fellow cyclist who happened to be going the same way. Which, despite my very best efforts, included the hotel I’d chosen for the night. Deftly selected because I thought it unaffordable for him, albeit well within my own budget. It worked. He disappeared. First assuring me, as far as I could ascertain, that next morning he’d be heading back from where we’d come.

Departure the following day. He was waiting. Followed me back to the main route along the valley. We parted company, heading off in opposite directions. Or so I thought. Twenty minutes later and he’d caught up with me again. I was beginning to feel very uncomfortable. Knew he had a reasonable amount of money on him, ample to stay in the hotel I’d used the previous night. But he hadn’t. Which made me think that perhaps this wasn’t a regular income, more his savings. Eeking them out. Very troubling.

Friendly he might have been but I began to wonder about loco parentis. Just exactly who was he, and how old? I’d been unable to find anyone who could translate my concerns, and my phrase book wasn’t any help. Began to toy with finding a police officer to help resolve the situation. But deterred by the language barrier. And I’d already quite a distance to cover before dark. Delay would be unwelcome.”

A difficult situation – but not of my making. I couldn’t stop him riding with me, but if he couldn’t keep up? That was another matter. Force him to go home. Wherever that was. Best for both of us I suspected. So that’s what I did. Suddenly opening up the pace, sustaining it for perhaps twenty miles. Seeking to get an edge over him. Flat, fast riding. He kept up for quite a while, then indicated he was beginning to struggle. I stuck with it, opening up the gap. Unceasing, relentless riding. And then he was gone. Cruel to be kind.