An Italian court has approved the extradition within 35 days of a suspect wanted in connection with the failed bomb attacks in London on 21 July.
Hussain Osman has been held in a Rome prison
Hussain Osman, also known as Hamdi Issac, will fight the decision at the Italian supreme court, his lawyers say.
The 27-year-old, who was arrested in Italy one week after the attacks, is accused of trying to blow himself up on a Tube train at Shepherd's Bush.
Three other men have been charged in the UK with the failed London bombings.
The 35-day delay before Mr Osman's extradition is to allow Italian police the opportunity to finish their own investigations into his activities.
Mr Osman's lawyers have said he will appeal the extradition.
They have 10 days to lodge an appeal, and then the supreme court has 15 days to make a final ruling - meaning that Mr Osman, who was arrested on 29 July, could be back in the UK by the end of September.
To secure the extradition, the lawyer acting on behalf of the UK government had to provide "clues" showing that what the suspect had in his rucksack on 21 July was intended to kill, said the BBC's Rob Watson in Rome.
He added: "Clearly that is what the Italian judges have believed, but it is certainly true that (his) lawyer had argued, 'look, we want more evidence about what was in that rucksack' and, I suspect, that will be in part the basis of her appeal to the Supreme Court."
The court case was seen as a test case for the new European Arrest Warrant, which is intended to speed up extradition in such cases.
Ibrahim Muktar Said, 27, Yassin Hassan Omar, 24, and Ramzi Mohamed, 23, appeared before magistrates on Bow Street magistrates sitting at Belmarsh high security prison in south-east London, last week.
They are charged with attempted murder and possessing explosives following alleged attempted bomb attacks on three Tube trains and a bus.
One charge faced by Manfo Kwaku Asiedu, 32, relates to an unexploded device found two days after the bomb attempts.
The four men - who are also charged with conspiracy to murder - were remanded in custody for three months and will next appear in court on 14 November.
The failed 21 July attacks took place two weeks to the day after four suicide bombers killed 52 passengers on the London transport network.