The study, by former Lib Dem leader Sir Menzies [Ming] Campbell, calls for major changes to the treaty, which is being used to demand the extradition of Asperger’s sufferer Gary McKinnon.
Sir Menzies says that it must be reworded so British citizens are afforded the same legal protection as their US counterparts.
The report, commissioned by Nick Clegg, contradicts the findings of the ‘whitewash’ Sir Scott Baker review into the deal, signed by Labour with the Bush administration in the aftermath of 9/11.
Sir Scott’s study for the Home Office concluded the Extradition Act was not biased, even though seven times as many Britons have been extradited as Americans. At the moment, ‘probable cause’ has to be shown before a UK request for extradition of an American citizen will be granted, with US citizens having the right to a court hearing to examine the evidence against them.
But the US must show only that there is ‘reasonable suspicion’ that a person demanded from Britain has committed an offence. The most high-profile victim of the Act is Mr McKinnon, 46, who faces being hauled to the US for crimes committed from the bedroom of his North London home.
He hacked into Nasa and Pentagon computers while looking for evidence of ‘little green men’.
Medical experts say he is likely to take his own life if extradited.
Sir Menzies, who is a QC, says he ‘respectfully disagrees’ with the findings of the Baker review, which Home Secretary Theresa May is currently considering. He said: ‘To put the matter as simply as I can, one may have a “suspicion” that someone has committed a crime, but that is a different and lower standard than being satisfied that it is “probable” that a crime was committed by that person.
‘The proper course should be to raise the British standard to the American one, so that UK citizens do not suffer a disadvantage compared to their US equivalents.’
It comes as MPs prepare to debate the plight of Mr McKinnon and extradition tomorrow. Last night his mother, Janis Sharp, urged politicians including Mr Clegg to honour promises to tackle the scandal.
She said: ‘The new report is the third concluding that the treaty is unequal and should be changed, as promised pre-election by both parties now in government.’
Sir Menzies also calls for the introduction of a so-called forum bar in cases where the US is seeking extradition for crimes which were committed in the UK.
Currently, British prosecutors decide in private if they think the case should be tried here.
Sir Menzies said: ‘In the interests of transparency … the decision should be taken by a judge in open court,’ a procedure ‘which is commonly called “forum bar”.’
He added: ‘If the present British government is to fulfil its duty to protect the rights of its citizens … and at the same time meet its treaty obligations, such a change is both necessary and possible, not least to restore public confidence.’
Mrs May is deciding whether she can halt Mr McKinnon’s extradition on the basis of the medical reports. A decision will be announced by October 16.