He had been suffering from cancer for two years.

The Welshman had joined the BBC in 1979 and had commentated on every Olympic Games since Los Angeles 1984.

Fenner had joined the Royal Dutch Gymnastics Federation (KNGU) as a consultant in 2010 and was appointed head coach of the men's team in February 2012.

Under Fenner, Epke Zonderland won the Olympic gold medal on the horizontal bar at London 2012. 

The Dutch men had also risen from 17th at the 2010 World Championships at Rotterdam to 11th in Glasgow last year. 

Earlier this year, the Dutch men qualified a full team for next month's Olympic Games.

Fenner, though, had been unable to travel to the qualifying competition in Rio de Janeiro in April because he was too ill. 

"It is a black day for gymnastics in the Netherlands, Great Britain and beyond," Hans Gootjes, technical director of the KNGU, said. 

Fenner's coaching career had started more than 40 years ago at the Bush Harlow Gym Club in London.

Louis Smith, Britain's three-time Olympic medallist, left a tribute on Twitter.

"Truly saddened to hear of Mitch Fenner passing," he wrote. 

"I grew up hearing his commentary in gymnastics. 

"He was such a good friend. I will miss you."

Barbara Slater, director of BBC Sport and herself a former Olympic gymnast , said: "For many years Mitch has used his first-hand experience of working within the sport to provide our viewers with an expertise and detailed insight that was second to none. 

"He will be missed by all of us at BBC Sport and our thoughts are with his family and friends at this time."