World champion Ben Proud was disqualified from the 50-meter butterfly at the Commonwealth Games on Thursday and lost an appeal against the decision.

Proud, who is also the reigning Commonwealth champion in the 50 butterfly and 50 freestyle, won his preliminary heat by nearly a body length but that was annulled after a referee disqualified the Englishman for movement on the starting blocks.

Proud challenged the decision but it was upheld by an independent appeals board.

"I am in the shape of my life and am gutted to miss out on the opportunity to show what I can do," Proud said.

He blamed over-eagerness in wanting to make an early impression at the Gold Coast Aquatic Centre.

"Coming into the competition there is always apprehension ahead of the first race," he said. "With fans in the crowd, I wanted to give them something to cheer about by delivering a fast time.

"Unfortunately before the start signal I was judged to have moved my leg and the referee deemed this enough for a disqualification."

Even Proud's rivals were sympathetic.

"That is a shame for the competition," Australian swim coach Jacco Verhaeren said. "It's not the same (without Proud) because he showed a world-class time there, but rules are rules."

South Africa's Chad le Clos ended qualifying with the fastest time.

"I would prefer to have Ben in the race and come second to somebody who is competitive with me," le Clos said.