British climber Kenton Cool reached the summit of Everest on Friday, his website announced, fulfilling an 88-year-old promise to carry an Olympic gold medal to the top of the world's highest peak.

Cool, 38, reached the summit for a 10th time at 4:45am (0900 AEST), breaking his own British record for the most successful ascents of the 8,848-metre (29,029-foot) mountain.

He was carrying one of 21 golds awarded to members of the 1922 British Everest expedition at the 1924 Winter Olympics, in an era when mountaineering was included as an Olympic sport.

The 1922 expedition stalled 500m from the summit, failing in three attempts to reach the top.

Lt Col Edward Strutt, a member of the team, had pledged that at the very next opportunity one of the gold medals would be taken to the top of the world -- a promise that until now had remained unfulfilled.

The medal Cool carried was awarded to expedition member Arthur Wakefield and was entrusted to Cool's team by Wakefield's grandson Charles.

"To have reached the summit of Everest 10 times is something I am immensely proud of," Cool said in a message via his website.

"Honouring the British team of 1922, particularly Arthur Wakefield, and fulfilling The Olympic Games Pledge is something I have wanted to do for a long time and to do this in the year that the Olympic Games comes to London makes it even more special."

Another famous member of the 1922 expedition was the British climber George Mallory who was to die on the mountain during another unsuccessful ascent two years later.

New Zealander Sir Edmund Hillary and climbing companion Tenzing Norgay are credited with being the first to reach the summit of Everest, on May 29, 1953.