Flash Crash trader Navinder Singh Sarao fails to post £5m bail, says he was just 'being good at his job'

Hound of Hounslow asked the court: 'How is this allowed to go on, man?'

Appearing at Westminster Magistrates court, Sarao refuted the allegations

Navinder Singh Sarao, the London trader blamed for the 2010 Flash Crash, will remain in custody after failing to meet a £5 million bail.

The so-called Hound of Hounslow was arrested last month after US authorities alleged his trading activities contributed to a sharp stock market plunge that wiped billions of dollars from the value of American shares in a matter of minutes.

He has been charged with wire fraud, commodities fraud and market manipulation and US prosecutors want him to be extradited.

Appearing at Westminster Magistrates court, Sarao refuted the allegations saying: "I haven't done anything wrong apart from being good at my job.

"How is this allowed to go on, man?"

Last week he was given an extra seven days to come up with £5 million bail money set by a judge.

Appearing today at Westminster Magistrates court, the trader, who lives and works from his parents' modest Hounslow home, again did not satisfy his bail conditions.

Sarao's lawyers instead asked that he be freed until an extradition hearing in exchange for a £50,000 security put up by his parents, according to reports.

Sarao, who the FBI has accused of stashing up to £26 million in offshore bank accounts in the Caribbean, has reportedly been unable to get hold of the £5 million due to an asset freeze imposed by the US.

District Judge Elizabeth Roscoe declined to modify the bail.

The 36-year-old was returned to Wandsworth prison following the hearing.