Britain's Tom Daley wraps a towel around his eyes in between dives in the men's synchronised 10m platform final during the London 2012 Olympic Games at the Aquatics Centre July 30, 2012.??[Photo/Agencies]

LONDON - British police arrested a man on Tuesday after offensive tweets were sent to British diver Tom Daley when he failed to win a medal in his first event at the London Olympics.

The Olympic poster boy and his partner Pete Waterfield were in with a chance of grabbing the host nation's first gold of the Games in the synchronised 10-metre platform event on Monday, but fluffed their fourth dive and wound up just outside the medals.

Daley, whose father Robert died from cancer last year, repeated a tweet from user @Rileyy_69 to his followers that said: "you let your dad down i hope you know that".

The diver responded: "After giving it my all ... you get idiot's sending me this."

The user later apologised.

"A 17-year-old man was arrested ... in the early hours of this morning, Tuesday, at a guest house in the Weymouth area on suspicion of malicious communication," police said.

Britain's chef de mission Andy Hunt said the tweets were "completely unreasonable and a threat" but said Daley was "unaffected". Daley will compete in the individual 10-metre platform event starting on Aug. 10.

"Everyone knows if you use social media extensively you get bad as well as good," Hunt told reporters. "If you open the door people come through it as well as go out the other side and we have been very clear about that. We have put out a lot of guidelines and a lot of education about this." ? ?

Twitter, a microblogging site which allows users to send short messages to each other and advertise views to a potentially huge audience, has hit the headlines at the Olympics after some ill-considered tweets by athletes.

Swiss soccer player Michel Morganella was expelled from the Olympics on Monday for a tweet which the Swiss team said "gravelly insulted and violated" the dignity of South Korea after his team's 2-1 defeat.

Greek triple jumper Paraskevi Papachristou was withdrawn after a tweet which was criticised as racist. ?

But Twitter has also given a platform for athletes to protest against Olympic rules that they disagree with. Some US athletes have posted tweets against restrictions on the promotion of non-official sponsors.????