As the 'NatWest three' are taken to America, the Home Office is stepping up its efforts to persuade the US Senate to ratify the controversial extradition treaty.
Home Office minister Baroness Scotland was flying to Washington DC on Thursday, where she was set to call on her American counterparts to sign up to the agreement.
While the Bush administration is continuing to back the deal it agreed to, the Senate must approve the treaty by a two thirds majority before it can take effect.
The failure of the US to ratify its side of the deal, which would widen the grounds on which US citizens can be extradited to Britain, has come in for particular criticism.
Meanwhile the three bankers at the centre of the row - David Bermingham, Giles Darby and Gary Mulgrew - have been handed over to the US authorities.
They are expected to attend a bail hearing in Houston, Texas on Friday.
Mark Spragg, solicitor for the three men, said: "It's a very sad day. They have said goodbye to their families and they have no idea when they are going to come back.
"It's all so unnecessary, that's the real problem here.
"This could easily have been tried in the UK. That's where the victim is, that's where all the witnesses are, but no, the government insisted on them being extradited on a very unfair, one-sided treaty.
"I just hope that all the media pressure is going to convince the government that there's definitely something wrong with this treaty and it must be altered and there must be provision put in to safeguard UK people being extradited to America."
In the Commons on Wednesday, Tony Blair sought to tackle concerns over the extradition agreement by saying that the US had given assurances on how the men would be treated.
"The American prosecutors will not oppose bail as long as appropriate conditions are put in place by the court or are agreed by the defendants," the prime minister told MPs.
But in the emergency debate that followed, MPs voted to adjourn the Commons early in what was seen by some as a symbolic protest against the US's failure to ratify its side of the extradition treaty.
The controversy surrounding the extradition took a further twist on Thursday when a possible witness was found dead.
