Navinder Singh Sarao, the British financial trader accused of helping trigger a multibillion-dollar Wall Street crash, has enlisted the services of American lawyers as he faces up to a potential trial in the US where he could be handed a 380-year jail sentence.
Sources close to the so-called "Hound of Hounslow" told the Press Association that Mr Sarao has added to his British legal team ahead of an appeal in the High Court on October 14, where he will fight a March ruling saying he could be sent to stand trial in the US.
Mr Sarao's UK solicitor, Richard Egan - partner at Tuckers Solicitors, warned that if the ruling goes against the trader "it might be that we have nowhere else to go".
He added that the "bar is very low" for US authorities.
"For the US, the bar is very low, they don't have to prove any facts. All they have to allege is that it is a crime in the US and the UK, that his conduct amounts to an offence in the UK, that he committed a fraud. We are arguing that it doesn't amount to that," he said.
Mr Sarao, 37, is wanted in America over allegations he helped cause the 2010 Wall Street "Flash Crash" from his parents' home 3,500 miles away.
He faces 22 charges, which carry sentences totalling a maximum of 380 years, over claims he contributed to the Dow Jones Industrial Average plunging 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 US dollars on May 6 2010, the day of the crash, part of illegal earnings of more than 40 million dollars (£26 million) over a five-year period.
Legal experts believe that Mr Sarao faces an uphill battle against extradition.
Andrew Katzen, partner at Hickman & Rose, said: "It looks as though Mr Sarao may face an uphill battle. The courts balance the rights of individual defendants with the 'powerful public interest in honouring extradition agreements with friendly states', such as the US - and often decide that the need for international cooperation in criminal justice takes priority over the little guy."
Mr Katzen said that Mr Sarao's "best hope" is arguing a lack of dual criminality.
"If Sarao's team can convince a High Court Judge that this conduct was not an offence in the UK, he will be staying in Hounslow for the time being," he added.
If he fails, however, then the trader faces the prospect of trial by jury in a Chicago court, although he could strike a plea bargain with US authorities.
According to Mr Katzen, the battleground for any trial could centre on whether Mr Sarao's use of a modified high frequency trading programme, where he repeatedly placed and within milliseconds cancelled orders, amounted to "normal trading practice" - and if not, whether it is considered honest behaviour.
He said: "This technical challenge may be an attempt to put in context the issue of dishonesty. Otherwise there is a danger that the trial could be another exercise in 'banker bashing', a popular sport on both sides of the Atlantic.
"One thing seems clear: Mr Sarao isn't your average 'Wolf of Wall Street' and shouldn't be viewed as such."