A British citizen accused of plotting to blow up targets in the UK only confessed after being tortured in Pakistan, a trial has heard.
Mr Amin (bottom left) says he was tortured by the Pakistani authorities
Salahuddin Amin, 31, from Luton, Bedfordshire, was detained in April 2004 and held for 10 months by Pakistan's ISI security service.
Patrick O'Connor QC said his client would tell the jury about the torture.
Mr Amin and six other men deny conspiring to cause explosions likely to endanger life.
His co-defendants were arrested after 600kg of fertiliser was found at a storage depot in Hanwell, west London, in March 2004.
Mr Amin handed himself into Pakistani authorities in April 2004 but was held without charge for 10 months before being flown back to Britain where he was arrested and then charged.
Mr O'Connor said of his client's time in Pakistan: "He was subjected to inhuman and degrading treatment, assaulted repeatedly in interview, was threatened with worse and witnessed the most appalling brutality to others."
The prosecution alleges the defendants were part of a cell linked to al-Qaeda which was targeting utilities, the Bluewater shopping centre in Kent, and the Ministry of Sound nightclub in London.
Mr Amin, who was giving evidence at the beginning of his defence case, admitted he had celebrated when he heard of the 9/11 attacks in the United States.
He said he was in the city of Rawalpindi in Pakistan when he heard about the attacks and said he became "carried away" by the "joyful" mood of local people, who saw the US as an enemy of Islam.
Mr Amin said: "People said that America was under attack and they were joyful and happy about it and were celebrating and handing out sweets.
"America was against Islam and I was happy that America was under attack."
But he said he changed his mind about it when he discovered the death toll and saw pictures of people jumping from New York's World Trade Center.
"I felt very sad because innocent people were dying and the way they were jumping out of buildings was terrible," he said.
Mr O'Connor asked him: "Is it something you approved of?"
"No," he replied.
Earlier Mr Amin said he had grown up as a non-religious Muslim, drinking alcohol, dating women and rarely praying.
But he said his views started to change when he returned to Pakistan on holiday in 1999 and heard an "emotional" speech from a woman who was recounting "atrocities" conducted against Muslims in "Indian-occupied Kashmir".
He said he began giving money to the Kashmiri cause and then began to pray and attend his local mosque in Luton.
In November 2001 he left Luton and moved to live in Pakistan. The court heard that just before leaving he took out two loans, for a total of £21,000.
Mr O'Connor said Mr Amin told Abbey National that one of the loans was for "home improvements" and he asked his client: "Did you knowingly act dishonestly?"
"Yes," Mr Amin replied.
"What were you intending to do with the money?" asked Mr O'Connor.
"[It was] for the cause, and for myself."
"The cause?" asked his lawyer.
Police found 600kg of ammonium nitrate in a west London lock-up
"The Afghan jihad. I was thinking I could give it to the fighters or to the refugees."
Later he said he gave £12,000 to a man in Pakistan who had connections with both "the resistance" in Afghanistan, and to refugees from the US-led invasion.
Seven men deny conspiring to cause explosions likely to endanger life between 1 January 2003 and 31 March 2004.
They are Omar Khyam, 25, and his brother Shujah Mahmood, 19, both from Crawley, West Sussex; Waheed Mahmood, 34, and Jawad Akbar, 23, also of Crawley; Salahuddin Amin, 31, from Luton, Bedfordshire; Anthony Garcia, 24, of Barkingside, east London; and Nabeel Hussain, 21, of Horley, Surrey.
Mr Khyam, Mr Garcia and Mr Hussain deny a further charge under the Terrorism Act of possessing 1,300lb (600kg) of ammonium nitrate fertiliser for terrorism.
The brothers also deny possessing aluminium powder for terrorism.