The former champion jockey Kieren Fallon was charged today as part of an investigation into alleged horse racing corruption, police said.
Fallon was one of 28 people answering bail at Bishopsgate police station in the City of London today in connection with the inquiry.
The six-times champion jockey, who won the Irish Derby yesterday, was charged with conspiracy to defraud, police announced.
Former racing syndicate director Miles Rodgers was also charged with conspiracy to defraud and an offence under the Proceeds of Crime Act.
The City of London Police investigation - codenamed Operation Crypton - has been hanging over the sport for more than two years.
The inquiry has been looking at more than 80 races and more than 130 officers have worked on the case.
Police said that the men had been charged in relation to allegations of fixing the outcomes of horse races between December 1 2002 and September 2 2004.
Fallon, 41, from Ireland, is accused of conspiring to defraud customers of the online betting exchange Betfair.
Rodgers, 37, of Silkstone, South Yorkshire, was also charged with conspiring to defraud Betfair customers and an offence relating to money laundering allegations.
Flat racing champion Fallon arrived at the police station earlier this morning, at 9.15am, wearing jeans and a dark top, and had slipped inside the front entrance without speaking to waiting reporters.
He left the police station just over 20 minutes later accompanied by another man dressed in a suit, thought to be his lawyer.
Both of them got into a silver Mercedes before being driven away.
Fallon made no comment as he was rushed out of the building.
Rodgers arrived a few minutes later.
At least 19 addresses have been raided in connection with the City of London Police investigation.
The police swoops followed alleged irregular betting on the internet exchange Betfair.
Betfair passed records from its tracking of betting patterns to the Jockey Club.
It in turn called in the City of London Police, who have the country's largest financial fraud investigation team.
Fallon and Rodgers were released on bail after being charged and are due to appear at City of London Magistrates' Court on July 17.
The police's long-running investigation is the largest of its type undertaken by the force. The first arrests were made in September 2004.
Police later said that three other people had also been charged in relation to the investigation.
They included jockeys Darren Williams, 27, of Leyburn, North Yorkshire, and Fergal Lynch, 28, of Boroughbridge, North Yorkshire.
Both have been charged with conspiracy to defraud Betfair customers and are due to appear in court on July 17 alongside Fallon and Rodgers.
Also charged this morning was Joanne Richardson, 27, of Silkstone, South Yorkshire, who is accused of an offence under the Proceeds of Crime Act.
City of London Police added that one person answering bail this morning had been released without charge.Reuse content