Italy's highest court of appeal is due to hear an appeal by one of the suspected London bombers against extradition to the UK.
Hussain Osman has been held in a Rome prison
Hussain Osman, 27, accused of trying to blow himself up on a Tube at Shepherd's Bush, was arrested in Italy a week after the failed attacks on 21 July.
On 17 August, an Italian court ruled Mr Osman - also known as Hamdi Issac - could be extradited within 35 days.
Three other men have been charged in the UK with the failed London bombings.
The court case has been seen as a test case for the new European Arrest Warrant, which is intended to speed up extradition in such cases.
Four judges will meet to decide whether to allow the appeal of Mr Osman.
Court sources say the appeal is likely to be rejected, given that the suspect has already admitted to both Italian and British police - according to his lawyer - that he was present at Shepherd's Bush underground station on the day of the failed bombing.
The suspected London bomber was arrested in Rome at the end of July after telephone calls he made from a mobile phone enabled him to be traced to his brother's apartment in a suburb of the Italian capital.
He has been held in isolation in Rome's Queen of Heaven prison pending a final decision on the British government's request for his rapid extradition under the new procedure of the European arrest warrant.
The appeal proceedings will be held in private.
According to the Italian lawyer representing the British government in this extradition case, the Crown Prosecution Service has already arranged for the suspect to appear before a British court together with other suspects already being held in London.
If the Italian appeal court decides in favour of the British government, the suspect is expected to be sent back to London not later than 21 September.