The trial in Egypt of imprisoned Dublin man Ibrahim Halawa has been adjourned until Saturday.
The Firhouse resident has had proceedings postponed or delayed 10 times since he was first arrested in August 2013.
Proceedings were adjourned again in Cairo yesterday - where he is standing trial alongside 490 other defendants. He was arrested during a day of protest in Ramses Square following the ousting of President Mohamed Morsi.
"Ibrahim and his family's appalling ordeal must end - and he should be immediately and unconditionally released and allowed to return home to Ireland," director of Amnesty International Colm O'Gorman, said yesterday. He said that the fact that he was in prison for 850 days was "unacceptable".
"Two days ago he turned 20, the third birthday he has spent in horrific circumstances in an Egyptian prison cell. Amnesty International remains gravely concerned for his mental and physical wellbeing, and again calls for his immediate and unconditional release."
The human rights watchdog has declared the young man a prisoner of conscience.
Amnesty has conducted its own investigation of the case and determined that Ibrahim is innocent.
Meanwhile, the Egyptian ambassador to Ireland, Soha Gendi, has issued a statement addressing what she says are unfounded accusations around Mr Halawa's case.
He is accused of "being a culprit in the felony of participating in a mob that led to the crimes of deliberate and premeditated murder, also crimes of initiating arson in buildings, causing destruction, and of possessing arms not licensed for possession", she said.
Ms Gendi also said that the delays in the trial have been because of the various defence teams involved who wanted proceedings pushed back or didn't attend court dates. The ambassador said that the length of the proceedings reflect the serious nature of what she termed a "very serious terrorism case".
It has been alleged on several occasions that Mr Halawa has been tortured in both of the Cairo prisons where he has been detained. However, in her statement Ms Gendi denied that he had been ill-treated.
The Halawa family could not be reached for comment last night.