The Dutch world judo champion who hit a man after he threw a bottle on to the track at the start of the men's 100m final last night said it was an emotional reaction.

Edith Bosch said she had acted out of disappointment and disbelief when the incident unfolded in the Olympic Stadium.

The 32-year-old was standing close by when a green plastic drink bottle was thrown from the stands behind the start line.

She later told Dutch television station NOS TV: "I had seen the man walking around earlier and said to people around me that he was a peculiar bloke.

"Then he threw that bottle and in my emotion I hit him on the back with the flat of my hand.

"Then he was scooped up by the security. However, he did make me miss the final, and I am very sad about that.

"I just cannot understand how someone can do something like that."

Bosch's involvement was brought to public attention on Twitter, where she wrote: "A drunken spectator threw a bottle onto the track! I HAVE BEATEN HIM... unbelievable."

A man remained in custody at an east London police station today on suspicion of causing a public nuisance.

A police spokesman said a man had been heard shouting abuse and was then seen throwing the bottle immediately before the race, which was won by Jamaican sprinter Usain Bolt.

He said nobody was injured during the incident and the event was not disrupted.

Speaking after the race, US sprinter Justin Gatlin, who won bronze, said: "It was a little distraction and I didn't know what it was.

"But when you're in those blocks and the whole stadium's quiet you can hear a pin drop."

Bolt told reporters he had been unaware of the incident.

He added: "No, I keep hearing that. I don't know who would have done that."

Fellow Jamaican sprinter Yohan Blake said: "I was so focused I didn't see anything. I was so focused on just running to the line."

Gatlin said the incident had not affected the race: "You just have to block it out and go out there and do what you got to do.

"You can't complain about that, the race went on and it was a great race."

A Locog spokesman said: "A man was arrested inside the Olympic Stadium last night after throwing a plastic bottle on to the track just before the men's 100m final.

"The incident had no impact on the competitors or the event.

"Locog does not tolerate abusive or anti-social behaviour and will seek to remove people behaving in this way from its venues."