By Jon Silverman
Legal affairs analyst
The government rests its case for the 2003 Extradition Act on what it calls "proportion and balance".
The Enron Three plan to continue their fight against extradition
Put simply, it concedes that UK citizens have fewer means with which to fight an extradition request from the United States than under the 1989 Act.
But it argues that the US legal system operates to accepted standards of fairness and that the benefit, in terms of a sharp reduction in the time it now takes to extradite, is worth the price paid.
An average delay of 30 months between request and extradition of suspect has been cut to about seven months.
This brings the US broadly into line with arrangements throughout the EU under the European Arrest Warrant.
Since the 2003 Act came into force, 11 UK citizens have been extradited to the US.
One US citizen has been brought to the UK for trial.
Of the 11, none was a terrorism case.
It has been suggested that the US courts are interpreting their jurisdiction more widely than a decade ago, especially in financial crime, and that this carries a threat under the simplified 2003 arrangements.
So far, there are no statistics to back up that claim although the Enron Three - the British bankers facing charges over the collapse of the US energy giant - warn that if they lose their fight, in matters of criminal justice "Britain would have become the 51st state of America."
The one unarguable consequence of the 2003 Act is that there is now an imbalance in the extradition arrangements in force between Britain and the US.
The US government needs only to outline the alleged offence, the punishment specified by statute and provide an accurate description of the suspect sought.
To extradite from the US, Britain must prove "probable cause".
It is a lower threshold than prima facie evidence but nevertheless a legal hurdle to be overcome.
The senior legal officer of the human rights group, Justice, Sally Ireland, said: "This is a safeguard provided under the US constitution but we can't understand why the British government cannot make the same stipulation."
The government's answer is that it would be wrong to require more from the US than it requires from signatory countries to the European Convention on Extradition.
The prima facie requirement for such states - which include Russia and Turkey as well as EU states - was scrapped in 1991.
However, many of those countries - though not all - have reciprocated the arrangement with the UK. The US has not.
That did not weigh heavily with the High Court in the matter of the Enron Three but it may yet assume importance as the case progresses towards the House of Lords.