Andrew Symeou denies being in the club at the time of the incident
A north London student accused of killing a teenager in a nightclub has been refused bail by a Greek court.
Andrew Symeou is charged with the manslaughter of Jonathan Hiles, 18, of Cardiff, who died on the isle of Zante in 2007, allegedly after being punched.
Mr Symeou, 20, of Enfield, returned to Greece last week for trial after losing a High Court fight against extradition.
Bail was refused as Mr Symeou has no permanent address in Greece, campaign group Fair Trials International said.
Jago Russell, the charity's chief executive, said: "Despite the major flaws in the case against him, Andrew now faces the prospect of months in a Greek jail before his trial even starts.
"We will continue to work with his Greek lawyer to fight for bail and to persuade the Greek authorities to end this unfounded prosecution."
A spokesman for the campaign group said Mr Symeou would prepare his appeal against the decision over the next five days.
Jonathan Hiles represented the Great Britain roller-hockey team
Mr Hiles, who was in Britain's roller-hockey team, died in July 2007 two days after falling off a dance podium in a nightclub.
It is alleged that he lost consciousness when he was punched hard in the face.
Mr Symeou, a Bournemouth University student, maintains that he arrived in the club three hours after Mr Hiles was injured.
Campaigners said two of Mr Symeou's friends were "beaten, punched, slapped and threatened" by Greek police officers until they gave statements implicating him.
There was a long challenge in the UK against Mr Symeou's extradition, although he was eventually returned to Greece last week after the House of Lords refused to hear an appeal.