James Cracknell KOs partygoer

Olympic rowing gold medallist James Cracknell broke a knuckle knocking out a troublemaker at a birthday party, it is reported today.

The 6ft 5in double gold medallist reportedly floored the man at the party at the Purple nightclub, at Chelsea Harbour, organised by his wife, TV and radio presenter Beverley Turner, for his 33rd birthday.

A friend of the rower said: "This man started giving him hassle and took a swing at him. James just turned around and knocked him out.

"There was a crack and James cradled his hand. But at least he wasn't out cold like the other guy."

Cracknell, who was awarded the OBE last year, told a friend: "This guy came at me out of the blue and I acted purely in self-defence. It was a very unfortunate incident and I just want to put it behind me." Cracknell, a boxing fan, was seen on Saturday night at Amir Khan's fight against Mario Kindelan, showing his injured hand to former champion Nigel Benn.

The friend said: "He didn't want to go to his doctor and admit he hurt his hand throwing a punch. But when he found himself sitting next to Benn he asked for help. Benn took a look and assured him it would heal over time."

Cracknell, father of an 18-month-old son, Croyde, hopes to recover by 28 May when he will be reunited with his Olympic team-mates, Steve Redgrave, Tim Foster and Matthew Pinsent.

The four, who won gold at the Sydney 2000 Olympics, will row against the teams they beat to raise money for charity.

Last year Cracknell repeated his winning performance in Athens, gaining a second gold medal in a nail-biting final with Pinsent, Steve Williams and Ed Coode.