The government last night won a vote to overturn objections to a new treaty on extraditing suspected criminals to and from the US.
MPs voted 320 to 263 to reject three amendments voted by the House of Lords this summer that would have forced the US to provide evidence - rather than just information - before it was allowed to extradite a UK citizen.
The peers also wanted to give UK judges the power to refuse a request for extradition if the alleged offence was committed in Britain unless it was in the "interests of justice" to extradite them.
Critics argue the 2003 treaty signed with the US is unfair. While Britain must provide "probable cause" before demanding an American citizen be brought to trial in the UK, the US must only provide "information", a less strict requirement, to extradite UK citizens.
The issue gained a high profile this summer with the extradition of three bankers to the US, the so-called Natwest three, but there have long been concerns about the way the 2003 treaty - which replaced a 1972 agreement - was negotiated.
Home Office minister Joan Ryan told the Commons last night it would be a "bad day for international cooperation in the fight against crime" if the Lords amendments were approved, and would "wreck our ability to bring more fugitives from justice to book".
She rejected suggestions that the treaty was unequal, saying: "It is rough parity - the highest level of reciprocity that is possible between two legal systems." Referring to the level of evidence required by the US and UK, she said: "The information is evidence."
However, shadow home affairs minister Edward Garnier argued: "Information is a different legal concept from probable cause, which is based on evidence."
Former Conservative leader Michael Howard noted that Home Office minister Baroness Scotland had admitted in December 2003 that the test Britain had to meet "is a higher threshold than we ask of the United States, and I make no secret of that".
There were also concerns about how the 2003 treaty had been negotiated, with former Home Office minister John Denham admitting he knew little about it until he was asked to present it to the House of Commons.
Mr Garnier said the government's opposition to the Lords amendments was "unjust, unfair, undemocratic and damaging to the interests of this country and our citizens", and they should be approved to restore "mutual respect" between the UK and US.
However, the government won the day with a majority of 57, and last night home secretary John Reid said the Conservatives' opposition proved they talked tough on crime but could not back it up with action.
"Only last month, [David] Cameron spoke of his desire to 'get tough' on white collar crime, but today his party have demonstrated how hollow those words were," he said.
He added: "The British public will judge Cameron and his party on their actions, not words. No amount of presentation will allow Cameron to escape the reality of the Tory record - they have continually opposed Labour's tough measures on crime."