But what has impressed him most, he says, is the friendliness and hospitality of local people, to the point of their sharing their tiny, modest woodland houses with him and providing anything else he needed, one of the most important things being local knowledge.

"When a pack of Tibetan mastiff were attacking us, several local men rushed in on their motors and drove off the big dogs. Those encounters with locals really have been the highlight of the journey."

Dykes, who studied outdoor education at college, said he had long wanted to travel the world, and first visited China, which had been at the top of his to-see list, in 2010, when he was 19. "As a child I read a lot about China and was always attracted to this ancient and mysterious country."

His first brief trip to Beijing and Shanghai served only to whet his appetite for more travel. Two years ago he began to prepare for the Yangtze expedition, including fitness training, high-altitude training, route planning, Chinese-language learning and finding out about local conditions.

"My adventures teach me to put things into perspective and never take things for granted. Hard work, persistence, dedication and good management of your expectations are my secret to complete 'mission impossible'."