The notorious hook-handed British hate preacher Abu Hamza claimed he was tipped off by militant contacts in Afghanistan about the September 11 attacks four days before planes struck the World Trade Center in 2001, court papers revealed Monday.

Hamza, 59, said he was warned that “something very big will happen very soon” and he interpreted the message as an impending terrorist attack on the U.S., according to a 124-page court submission obtained by Britain’s The Sunday Times.

“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 neighbors in his Pakistan time (1991-93) saying ‘Something very big will happen very soon’ (meaning USA),’" court documents obtained by The Sunday Times stated.

The former imam, who remains behind bars in a Colorado prison, said he believed the phone in his London home was being “tapped” by police. Hamza became a leading figure in Britain’s Islamic scene in the late 1990s — most famously preaching in Finsbury Park Mosque.

The phone calls also reportedly showed that Hamza was an MI5 agent, the U.K’s domestic counter-intelligence and security agency, and operating under the code name “Damson Berry.”

Hamza was sentenced to life in prison in the U.S. after he was convicted in 2015 of terrorism and kidnapping. He was thrown in prison without the possibility of parole, but is currently appealing to return to the U.K., claiming he’s being kept in “inhuman” conditions at the “supermax” prison.

Court documents said Hamza was being kept in a tiny “cage” and that “the stumps in both arms are subject to regular outbreaks of infection, which have been increasing in severity,” the Telegraph reported.