A British financial trader accused of helping trigger a multibillion-dollar Wall Street crash from a suburban home in west London can be extradited to the United States to stand trial, a judge has ruled.
Navinder Singh Sarao, 37, dubbed the Hound of Hounslow, is wanted in America over allegations he helped cause the 2010 Wall Street "Flash Crash" from his parent's home 3,500 miles away.
Sarao faces 22 charges which carry sentences totalling a maximum of 380 years over the financial crisis, which saw the Dow Jones Industrial Average plunge 600 points in five minutes, wiping tens of billions of pounds off the value of US shares.
American authorities claim the Briton made 875,000 dollars on May 6 2010, the day of the crash, part of illegal earnings of more than 40 million dollars (£26 million) in five years.
District Judge Quentin Purdy ruled on Wednesday that Sarao could be sent to stand trial in the US in an extradition hearing at Westminster Magistrates' Court.
Lawyers for Sarao, who argued his actions did not constitute a crime, said outside court that they will lodge an appeal once Home Secretary Theresa May makes her final decision in the case.
Sarao's lawyer Richard Egen told reporters outside the courtroom: "We still think we have a strong argument and we will be appealing the decision (of the court) once the Secretary of State makes her decision.
"We are very disappointed. We think we had a strong argument but we will be going to the Court of Appeal to make our argument there."
Mrs May is the final arbiter on extradition requests and has two months in which to either grant or refuse the US request, Judge Purdy said.
Sarao, wearing a red jumper and black trousers, was released on bail after the short hearing.
Sarao is accused of "spoofing" - a practice of bidding with the intent to cancel the bid before execution.
US authorities needed to prove dual criminality - meaning that an alleged offence must be a crime in both countries - in order to extradite him.
At an earlier hearing his lawyers argued that his actions were not criminal in this country, while the Americans said they were covered by several British fraud offences.
A previous hearing heard that Mr Sarao allegedly manipulated the market by making "false" and "fictitious" orders on the Chicago Mercantile Exchange (CME).
But his lawyers claimed that his orders "created true liquidity" and did not give a "false or misleading impression".
They also dismissed claims that he had a "meaningful, causal" link to the "Flash Crash" as "nonsense" and said he had stopped trading an hour before the market plunged.
In his written ruling, Judge Purdy said: "The causes of the Flash Crash are not a single action and cannot on any view be laid wholly or mostly at Navinder Sarao's door, although he was active on the day. In any event this is only a single trading day in over 400 relied upon by the prosecution."
But he wrote that the American authorities had made a convincing case for dual criminality.
He had earlier told Sarao in court that he could appeal to the Home Secretary "otherwise the case will be sent to the US for trial".
Sarao left court without commenting, flanked by his legal team.