A picture from the video clip the London organizing committee used to promote the logo for the 2012 Games.

A London 2012 spokeswoman said the concerns surrounded a four-second piece of animation shown at the logo's launch on Monday and recorded by broadcasters.

Emphasising that it was not the logo itself which was the focus of health worries, she said: "This concerns a short piece of animation which we used as part of the logo launch event and not the actual logo."

"It was a diver diving into a pool which had multi-colour ripple effects," the spokeswoman said.

Critics of the emblem have described it as "hideous", while organisers called it powerful and modern.

The clip's removal follows comments by Professor Graham Harding, an expert in clinical neuro-physiology who developed a test used to measure photo-sensitivity levels in animated TV material.

"The logo should not be shown on TV at all at the moment," Harding told the BBC. "It fails Harding FPA machine test which is the machine the television industry uses to test images."

He said the footage did not comply with regulatory guidelines.

Charity Epilepsy Action noted there had been reports that people had had seizures while watching the animated footage.

The BBC reported on its Web site that a listener had rung its London radio station to say he and his girlfriend had suffered seizures while watching it.