The three British bankers facing extradition to America over the collapse of Enron should be put on trial in the UK, say the Tories.
The NatWest executives say they should be tried in the UK
They are writing to Attorney General Lord Goldsmith asking him to consider the case again.
Shadow attorney general Dominic Grieve said extradition of the three NatWest executives, who deny the claims, could bring UK justice into disrepute.
It comes after Tony Blair said he would try to ensure they got bail in the US.
The prime minister denied the fast-track extradition laws being used against the three were one-sided because the US had not ratified the treaty.
David Bermingham, Gary Mulgrew and Giles Darby have lost their court battles to stop their extradition.
They say they want to stand trial in the UK.
Mr Grieve is supporting their case, saying he knows of no reason why they should not be tried in the UK.
"It must be a legitimate source of public anxiety that, where the defendants are British nationals living in England and the alleged victim is a British corporation this case is not being prosecuted here," he says in his letter.
"If it were to be, then public disquiet would, I am sure, be entirely removed."
Mr Grieve says the American justice system strives for a fair outcome but involves shackling defendants, difficulties obtaining bail and different detention conditions.
"I would, therefore, be grateful if you would give further consideration to this matter so as to ensure that these defendants have the benefit of our own system of justice and the British public the benefit of seeing justice being done in respect of them," he tells Lord Goldsmith.
Liberal Democrat leader Sir Menzies Campbell has also complained the extradition arrangements, passed in 2003, are unfair.
He has suggested the trio will find it harder to get a fair trial if they are extradited as they are unlikely to get bail and will find it difficult to prepare a complicated defence case from inside a Texas jail.
Laws passed in 2003 mean the US no longer has to present a "prima facie" case when asking for somebody to be extradited.
But in the Commons on Wednesday, Mr Blair denied America was getting "preferential treatment".
Mr Blair said he understood the concerns of the bankers' families.
He said he was asking his officials to see whether "any support or reassurance" could be given to help those extradited get the chance of bail.