Three British bankers have lost their High Court battle against extradition to the US to face charges over the collapse of energy giant Enron.
The former NatWest executives deny any wrongdoing
Lord Justice Laws ruled that the case involving the former NatWest trio was "perfectly properly triable" in the US.
David Bermingham, Gary Mulgrew and Giles Darby have always maintained their innocence of "wire fraud" and say they should be tried by a UK jury.
The men will now try to take their battle to the House of Lords.
Enron collapsed in 2001 after admitting inflating profits and hiding debts.
The case has generated criticism of extradition laws that mean the US is not required to provide "prima facie" or solid evidence of wrongdoing to extradite a UK citizen.
Britain must still provide the US with evidence of "probable cause" if it wishes to extradite someone from America.
Mr Bermingham of Goring, Oxfordshire, Mr Mulgrew, of Sible Hedingham, Essex, and Mr Darby, of Lower South Wraxall, Wiltshire, have been accused of seven counts of "wire fraud" by the US.
The three are alleged to have conspired with former Enron executives over the sale of part of the company in 2000, which made them a total of $7.3m (£4.2m).
But the court dismissed their claims that because the offences they were charged with were not extradition offences, forcing them to stand trial in the US would be unjust and breach European human rights laws.
Lord Justice Laws said it would be "unduly simplistic to treat the case as a domestic English affair".
The judgement marks the first test case in the UK under the government's Extradition Act 2003 - which was developed in the wake of the 11 September attacks in 2001.
The decision prompted the men's solicitor Mark Spragg to warn that the case would have far-reaching consequences.
"The US justice system has a long and aggressive extra-territorial reach, and will increasingly apply for the extradition of UK citizens for allegedly criminal conduct committed against UK institutions," he added.
Speaking outside the court, Mr Bermingham added he was saddened that the government was using its citizens as "political currency".
The case has provoked widespread debate in the UK.
Oct 2001: Accounts black hole becomes public knowledge
Dec 2001: Enron admits inflating profit, files for bankruptcy
It emerges Enron used a complex web of transactions to hide debt
2002: Criminal inquiry launched
Jan 2004: Ex-finance chief Andrew Fastow pleads guilty, accepts 10-year jail term
Feb 2004: Ex-CEO Jeffrey Skilling pleads not guilty to fraud and insider trading charges
Jul 2004: Ex-chairman Ken Lay indicted
Company bosses are concerned that the treaty has created an unequal balance between the US and UK.
Conservative MP Boris Johnson said the "serious imbalance and asymmetry" of the treaty was a worry.
"(The US) can ... hoover over to America, as if by some electro-magnetic power, people against whom they're not obliged to produce any prima facie evidence - whereas we have absolutely no such corresponding right to extradite to Britain suspects that we want," he added.
Sir Menzies Campbell, the acting Liberal Democrat leader, said the government had failed to stand up for British interests.
"The truth is the government has been caught out here because it entered into an agreement with the United States, a treaty, which gives British citizens poorer rights than American citizens."
However, Home Office Minister Andy Burnham defended the extradition agreement saying the relationship between the UK and US was far more "in balance" in terms of the time any decision takes.
Enron's founder, Kenneth Lay, and former chief executive, Jeffrey Skilling, are currently on trial in Texas after pleading not guilty to more than three dozen counts of insider trading, fraud and lying on financial statements.