Mr Abbas has visited many JI bombers in jail and attended JI forums in central Java, where he was accused of being a traitor. Most importantly, he testified against Abu Bakar Bashir, who he said was appointed emir of JI.

The softy spoken Malaysian learned his weapons expertise from Afghan mujahedeen along the Pakistan border in the early 1990s, set up a military training camp in Mindanao in 1996, and trained dozens of JI members, as well as members of the Mindanao separatist movement in weapons use and military tactics. He was also appointed the head of one of JI's four Muslim territories, spanning the southern Philippines, and Sulawesi, Indonesia.

But he said he began to have doubts about his role in JI, and the aim of establishing an Islamic state, when he heard reports of the Bali nightclub bombings. He said he was opposed to the killing of innocent civilians, and was shocked to learn many Muslims had been killed in the blasts. 'The Koran says we can only kill in battle, not elsewhere,' he said.

After his arrest in 2003, he abandoned his fellow jihadis, and provided the police with information.

But Mr Abbas' position as police informer has won him more than a few enemies. Mr Bashir, the fiery cleric who Mr Abbas helped put behind bars for a few months, is 'probably not happy with him'.

And Muhklis (otherwise known as Ali Gufron) one of the three Bali bombers on death row for masterminding the attacks, has condemned him as an 'infidel' and a traitor to Islam. Radicals in Sulawesi, where a Muslim-Christian conflict raged from 2001 to 2003, called for his execution.

Mr Abbas said he and Muhklis - his brother-in-law - were locked in a battle for the souls of the imprisoned JI members. Muhklis has been trying to rally former or would-be supporters by smuggling out recordings of his prison sermons advocating violence, which are being sold on the streets of East Java.

'Muhklis has already told others that I'm not a Muslim any more,' said Mr Abbas. 'But he does not understand that some JI members agree, but most JI members disagree with his ideas.'

Mr Abbas, who speaks Arabic, said most of the JI members had been fed an idea that Islam supported violence, and had tried to turn a compassionate religion into one that idolised death more than life.

'The radicals say they're going on a hijrah, that they are going on a journey from life to death and that to die a martyr is better than to live among people not implementing sharia law,' he said. 'But I'm trying to bring them back to life, bring them back to reality. To convince them that we are born to do good deeds not born to die.'

But Mr Abbas, who has been arguing that Islam forbids violence outside of a war of self-defence, contends that he is winning this spiritual battle.

'One by one the JI members try to contact me. They are starting to understand me, starting to want to meet me, want to know more, want to hear directly from me,' he said.

If Muhklis and his fellow bombers try to spread a violent, destructive version of Islam, Mr Abbas believes it is important to promote Islam as a religion of peace.

'If they can fight, they can use the gun, then I also can use that,' he said, explaining that his weapons were a better understanding of his religion, and his faith.

Fashionably dressed in a well pressed striped shirt, glasses and jeans, it is hard to connect this man to a past filled with setting up secret military training camps, and weapons smuggling. He confessed that even as a Muslim militant he refused to give up wearing Levi's jeans, despite criticism that they were western.

But a hint of his cunning in his former life emerged when Mr Abbas described his escape from Malaysian police in 2001. He was picked up in Sabah, heading for the Philippines, because one of his colleagues was found with a bullet in his baggage.

At the time, Mr Abbas was the point-man for JI, organising the transportation of militants and weapons from Malaysia to the Philippines and Indonesia, and Malaysian police had begun arresting JI members for their plot to establish a Muslim state and blow up western facilities in Singapore and Malaysia.

Mr Abbas' name would have been on their wanted list, and as soon as they finger-printed him and sent his details to Kuala Lumpur, he would have been destined for a long jail term, as would his four JI companions.

But Mr Abbas put on a convincing Indonesian accent, and pretended he was one of thousands of Indonesian illegal workers who overstayed his visa. This performance meant two of his companions went free, while just one, as well as Mr Abbas, was detained by police.

At the local police station, he made a dramatic escape out of the front gates, rushing into busy traffic and ripping off his blue shirt to reveal a beige one underneath. Once across the road, he calmly stepped into a taxi.

Arriving at the home of a friend who had no idea he was a member of JI, he claimed his wallet had been stolen and asked to borrow a little money. He moved from friend to friend, picking up clothes and extra money: none of them had any idea that he was a senior JI leader.

Mr Abbas thinks that Mas Selamat bin Kastari, a JI member in Singapore who last month escaped from a toilet window in a high-security prison, might have plotted a similar escape. Police in the city state have launched a massive manhunt but, embarrassingly, have found no sign of him. Like Mr Abbas, Kastari organised smuggling routes between Malaysia, Singapore and Indonesia, and may have used information from his wife, that he patiently collected over weeks and weeks of casual inquiries about his friends, as to who had been picked up by the police. He might have then relied on people such as fishermen, who didn't realise he was a JI member, to help him escape to Malaysia or Indonesia.

Turning the tables on a terrorist outfit is a risky role. The evening before this interview, Mr Abbas received an anonymous threat in a text message from someone in Sulawesi.

Provided with police protection, Mr Abbas said he preferred not to dwell on the possibility that he might be assassinated.

'God knows everything, if someone plans that then God will know this, and I believe he will protect me,' he said with a grin.

The deradicalisation programme has not been without controversy.

It made headlines in Australia last October, when it was reported that a group of 20 repentant militants, including two men involved in the Bali bombings in which many Australians died, were invited to a breaking of the fast with the Indonesian police chief during the Muslim holy month of Ramadan.

The news reports said the police chief invited the bombers to a party. The then prime minister John Howard condemned the so-called 'b-b-que', saying it was extremely upsetting to Australians, and that the police chief was insensitive to the feelings of Australians.

Security analyst Ken Conboy, who has written a book on JI, said the deradicalisation programme, coupled with the swift arrest of any militants involved in attacks, had been highly successful.

'Indonesia has been a success story in terms of marginalising these violent radicals,' said Mr Conboy.

Deploying moderate clerics had been particularly effective, he said, in countering the radicals' arguments that suicide bombings were justified under Islam.

He said the movement had faltered because the top leadership had either been detained or killed, and the lower-level members were incapable of organising attacks, pointing out that there hadn't been a major attack since October 2005.

However, he did not rule out attacks 10 years or more further down the track.

'It's always possible people of like minds will rise from the ashes,' said Mr Conboy, pointing out that the sons of the bombers could form a new movement.

But for the moment, with most of the Mindanao and Afghan veterans detained, JI has no locations where it can provide the weapons and bomb training which led Imam Samudra and his cohorts to launch the 2002 Bali bombings and the smaller subsequent attacks.