The delay is to give Rome police time to pursue inquiries into Mr Osman's activities in Italy, where he lived for several years before moving to Britain and claiming refugee status under a false name and nationality.
It also allows time for Italy's highest court of appeal, the Court of Cassation, to rule on the validity of the court's decision. His lawyer, Antonietta Sonnessa, said she would appeal against the decision within the 10 days allowed. The judges must make up their minds within a further 20 days.
"The judges maintained that no further evidence was required and that there was no need for a forensic report on [Mr Osman's] rucksack as requested by me and the prosecutor. In my appeal I will insist on the necessity of a forensic report," she said. "There is no way he can have an unbiased trial [in Britain]."
The court's ruling will come as a relief to British authorities who have been pressing for a speedy extradition. The biggest threat to a prompt extradition came not from the defence but the prosecution. Had a clear link been established between the July 7 suicide bomb attacks, which killed 52 people, and the failed attacks of July 21, Roman prosecutors might have insisted that Mr Osman stay in Italy to stand trial for his role, if any, in the murder of an Italian woman who was one of the victims.
But no definite connection has been proved. Likewise the possibility of a "temporary extradition", allowing Mr Osman to be transferred to Britain then returned to Italy for trial, was also abandoned. The judges, however, made extradition conditional on the British authorities being willing to extradite Mr Osmanto Italy should the "investigative need" arise.
The extradition request said: "Hussain Osman, alias Hamdi Issac ... entered the Underground around 12.20 [on July 21] at Westbourne Park station. He was carrying a rucksack containing an explosive device ... He boarded a train and then tried to detonate the explosive device."
Shortly afterwards, a man resembling Mr Osman was filmed by CCTV - minus rucksack and shirt - on board a No 26 bus. Several days later he travelled to France on a Eurostar train, and from there to Rome.
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