"You know full well I am not guilty and that this accusation is false," Abu Qatada, in prison overalls, told the state security court in Amman.
Abu Qatada and his lawyer both contested the presence of a military judge among the panel of three trying the case.
This was "not in accordance with the Jordanian-British accord" which cleared the way for his client to be tried in the Arab country, charged Ghazi Dhuneibat.
After his deportation, Jordanian military prosecutors charged Abu Qatada with conspiracy to carry out terrorist acts. If convicted he could face a minimum of 15 years' hard labour.
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Britain's expulsion of Abu Qatada came after Amman and London ratified a treaty guaranteeing that evidence obtained by torture would not be used in his retrial and that the proceedings would be transparent.
The Palestinian-born preacher was condemned to death in his absence in 1999 for conspiracy to carry out terror attacks, including on the American school in Amman, but this was immediately commuted to life imprisonment with hard labour.
However, Jordanian law grants him the right to a retrial with him present in the dock.
Born Omar Mahmud Mohammed Othman in Bethlehem in the now Israeli-occupied West Bank, Abu Qatada has Jordanian nationality because the town was part of Jordan at the time of his birth.
Videotapes of his sermons were allegedly found in the Hamburg flat of 9/11 ringleader Mohammed Atta.
Top Spanish judge Baltasar Garzon once described Abu Qatada as Osama bin Laden's right-hand man in Europe, although he denies ever having met the late al-Qaeda chief.