For Sheffield student and kayaking enthusiast Tom Hunter, it was unforgettable.

"I was absolutely thrilled to take part and it was a fantastic experience," he said.

The 22-year-old, from Bradway, was among eight students from across the UK selected for the challenge, which involved enduring the awesome power of rivers in the Altai Mountains, where the borders of China, Kazakhstan, Mongolia and Russia meet, in Central Asia.

Some of the waters had rarely been explored before - and, on parts of the expedition, there could be days between sightings of other people.

Tom, who has been kayaking since he was 14, was chosen after applying for the challenge, organised by the British Universities Kayak Expedition, and standing out as one of the best entrants at a selection trial in Snowdonia, Wales.

The former Woodseats Venture scout was delighted to make the eight-man team, which also included 19-year-old Dave Burne, from Doncaster, a biochemistry student at Newcastle University.

The nine-week Four Borders Expedition started in Russia, where paperwork and preparations took much of the first week. But the students managed a couple of practice runs on the River Chuya - one of the toughest in the area, which tumbles through a gorge.

Tom, a student at Notting-ham Trent University, said: "Rivers are graded and this one was five plus. Six is unrunnable.