Counter terrorism police have won the right to force the author of a new book about terrorism to hand over his research.
By Richard Watson
The book is about Hassan Butt, a British citizen who admits that he acted as a recruiting agent for al-Qaeda and raised tens of thousands of pounds for terror networks.
He says he left his network after the London bombings in 2005 and is now is turning extremists away from terrorism.
Hassan Butt's co-author, an independent journalist, has been ordered to deliver draft manuscripts and notes for the book to the Greater Manchester Police.
By his own admission, Hassan Butt has been a terrorist supporter.
In an exclusive interview with BBC Newsnight, he described how he helped hundreds of British recruits get weapons training in Pakistan and Afghanistan in the autumn of 2001.
His network was offering young British Muslims the chance to fight with the Taleban against American and British forces.
"We had built links with organisations to get trained, we had built links with organisations which could get people across the border safely and securely," he told the BBC.
He said that his network helped more than 600 British Muslim extremists get terrorist training abroad.
One such jihadi was Mohammed Siddique Khan, who led the London bombers in the attacks on 7 July 2005.
After the fall of the Taleban in late 2001, he stayed in Pakistan, making contact with Al Qaeda.
"I got involved in terrorism - I guess that's the right word to use quite frankly. As a result of it I had to leave - my name was popping up in intelligence agencies," he explained.
He fled back to his home city of Manchester where he continued to recruit for the jihadi network.
He also became an expert fundraiser, collecting between £8,000 and £9,000 a month which he would send to Pakistan via a secret underground banking system known as "hawallah".
Hawallah banking works by word of mouth; there are no receipts and no records of transactions.
"Initial fund-raising would be door to door collection, outside mosques, fund raising events. But as my reputation grew I could approach richer people and businessmen."
He said "everyone knew" what the money was for.
Hassan Butt's extreme views were being fuelled by preachers like Abu Qatada who is accused of being Al Qaeda's spiritual leader in Europe.
Abu Qatada taught that the world was divided into two halves - the righteous land of Islam and the land of unbelief or war where killing civilians was "justified".
Hassan Butt used to think that Britain was within the land of war but when he began working with teenagers in Manchester he began to question this assumption.
"I started realising it's not as black and white - how could I justify killing these people because these people are living amongst us," he says.
But he told Newsnight that it was the attacks of 7 July on London which finally changed his mind.
"I realised that the jihadi network was not killing for the sake of Islam, it was killing for the sake of causing terror and causing havoc."
He says he stopped raising funds after 7/7 and as a consequence his terrorist leaders in the middle east demanded he travel to Dubai for a meeting.
He thought they were going to reassure him about his theological concerns, but instead they told him he needed "reprogramming" in Iraq where he would be expected to join the insurgency.
Realising that would be a one-way ticket, he travelled back to the UK. He says this point, in January 2006, was when he finally left the jihadi network behind.
Since then he has been working with some of his original recruits to turn them away from terror. His message now is very different: "Muslims are living in this country and accepted¿ they're equal citizens of the same state.
"We're born, raised and are planning to die in this country, so how can this country be a land of war?"
Last July, the Home Office invited him to discuss his ideas about tackling radicalisation with Home Office minister Tony McNulty. Yet at the same time Greater Manchester Police were investigating him as a terrorist suspect.
Hassan Butt says the continued police investigation is threatening is de-radicalisation work.
He says he has offered to speak to the police and will not deny his past.
"I'm more than happy to cooperate. If they want to charge me for things I've done in the past then say that."
The police investigation into Hassan Butt's past presents a dilemma for the authorities.
Should extremists be prosecuted for their alleged crimes of the past? Or should the government and the police work with them in the hope they will persuade other extremists to reform?