An extradition hearing involving Abu Hamza al-Masri has been delayed after the radical Islamic cleric had an operation on one of his arms.
The US is seeking the extradition of Abu Hamza
His lawyer said the 48-year-old, who is serving seven years for inciting racial hatred and soliciting murder, was not well enough to attend the London case.
The US wants Abu Hamza, whose hands are amputated, to face terror charges.
The House of Lords paved the way for the hearing after refusing him leave to appeal against his UK convictions.
He was originally arrested on an extradition warrant in May 2004 but the process was put on hold while he stood trial at the Old Bailey and then attempted to overturn the jury's verdict.
The extradition case, scheduled to last four days, was due to take place at Woolwich Crown Court in front of Senior District Judge Timothy Workman.
But Abu Hamza's barrister Alun Jones QC told the court his client was recovering from an operation on Monday to remove an inch of bone from one of his arms.
He said Abu Hamza, from west London, was given no notice of the procedure.
"He has not slept and he is in pain," he said.
"We do not consider he has sufficient ability to concentrate on his case."
Abu Hamza lost his hands and one of his eyes in a mine explosion while working on reconstruction schemes in Afghanistan in the 1990s.
He wore prosthetic fittings before being jailed, including a hook on his arm.
Mr Jones said he often accidentally bangs and scrapes his arms on metal surfaces in Belmarsh jail's high security wing.
The injuries can become infected and require further treatment, the court heard.
The hearing was adjourned until Thursday.