Imprisoned hate preacher Abu Hamza claimed that he was tipped off about the 9/11 attacks by militant in Afghanistan, four days before the terror attack took place, according to recently revealed court documents.

According to a report by the Sunday Times, Hamza said that the militant contacts called him in order to warn him about the attack by saying, “Something very big will happen very soon.”

Hamza, who is locked up in a Colorado prison, stated he perceived the messages as being about an impending terror attack in the United States; he also believed his house in West London was being “tapped” by police authorities at the time.

The information which was revealed in American court papers also stated that Hamza disguised himself as MI5 and Special Branch agent and used the code name “Damson Berry.”

Hamza also denied the fact that the call was made by members of the terror organization Al-Qaeda and stated that he thought “this news is widely spread and everyone is phoning friends…the intelligence [agencies] of many countries must have had an earful about it.”

The 124-page handwritten court document stated that Hamza was treated unfairly and “punished” after the 9/11 attacks.

The former imam of north London's Finsbury Park mosque is currently serving a life sentence after being convicted of terrorism offences in 2014.

In the court document, Hamza wrote in broken English: “What made pro-war governments and intelligence [agencies on] both sides of the Atlantic more furious about the defendant [Abu Hamza is] that defendant received a call from Afghanistan on Friday, Sept 7, 2001, from 2 of his old neighbours in his Pakistan time (1991-93) saying ‘Something very big will happen very soon’ (meaning USA).”

These revelations are likely to raise questions whether British authorities knew about such an attack and still failed to pass on the information to the U.S. authorities.

Hamza’s claim wasn’t independently authenticated but due to his standing in extremist circles, the revelations are believed to be plausible, said the report.

Last year Hamza demanded to be returned to return to the U.K. as he felt that the U.S. prison was too tough.

According to a report in December by the Telegraph, lawyers who represented Hamza stated that the latter would go back to a British jail “in a second” if he could.

Hamza who is currently serving the life sentence at the federal “supermax” facility, ADX (Administrative Maximum Facility) Florence, in Colorado, complained of the “inhuman and degrading” conditions in the prison and also stated that these conditions were violating his “human rights.”

Court documents which were submitted under his real name, Mostafa Kamel Mostafa, stated that his “cell-sized cage” was not suitable for a double-amputee person and also “the stumps in both arms are subject to regular outbreaks of infection, which have been increasing in severity.”

The court documents also said, “Mostafa [Kamel Mostafa] is permitted to one hour per day of recreation time outside of his cell... Even during that one-hour recreation, however, Mostafa is still confined within a cell-sized cage and is in that cage alone.”

Hamza was convicted for 11 counts of terrorism related charges which included his involvement in the kidnapping of 16 tourists in Yemen in 1998.