The UK government would be complicit in torture if it extradites anti-gay Muslim cleric Abu Hamza and his fellow terror suspects to the United States, a senior UN adviser has warned.

According to the Independent, Juan Mendez, a UN special rapporteur, last night wrote to the government warning that pushing ahead with plans to deport Hamza, 54, would breach the UN Convention Against Torture.

Mr Mendez claims the solitary confinement that Hamza would endure in an American “supermax” prison amounts to torture.

Yesterday, lawyers for Hamza asked the High Court for an injunction so they can carry out further medical tests on the radical cleric who’s described as being in “poor health”.

On Wednesday, Sir John Thomas QC, president of the Queen’s Bench Division, questioned whether new medical evidence on Hamza is reason enough to delay his extradition.

“There are excellent medical facilities in the United States.

“The sooner he stands trial the better. If he is at risk of a degenerative condition, the sooner he is put on trial the better. I don’t see how delay is in the interests of justice,” remarked Sir Thomas.

Abu Hamza’s lawyers said eight years in prison had led him to develop chronic sleep deprivation and mental depression.

He is also said to be suffering from memory loss, problems with his attention and is in need of an MRI scan to determine the health of his brain.

They argue he is unfit to stand trial.

Hamza is wanted in America over allegations that he plotted to set up a terrorist training camp and also over charges of conspiracy to kidnap Western hostages in Yemen.

Last month, the European Court of Human Rights rejected a bid by Hamza and four other suspects to halt their deportation cases.