Europe has become a hunting ground for al-Qaeda recruits. Largely disillusioned with US foreign policy, several young Muslims are making the journey east, some to become suicide bombers.
Peter Cherif was soon told he could never be alone with Barbara
In his new television series, Peter Taylor talks to a woman in Paris whose life was turned upside-down when her boyfriend went to fight in Iraq.
Barbara had known Peter since their schooldays.
"He was the clown in the classroom, always making everyone laugh," she told me.
"He was very gentle and always had time for everybody. He was like a big brother and protected me at that time."
Peter was like any other French teenager.
He enjoyed sport, hanging out with his friends and listening to French and American rap music.
The fact that Peter was a North African Muslim and Barbara was a white French teenager, half Christian and half Jewish, was not an issue for either of them.
Buttes Chaumont, the area where both lived in Paris, was reasonably well integrated and not the powder keg that the notorious banlieues of Paris were later to become.
In time, Barbara and Peter started going out together.
Barbara always respected Peter's religion and it never got in the way of their relationship.
He used to pray at home, fasted at Ramadan, and behaved just like other Muslims.
Then gradually things began to change.
One day he told her he was going to catch up with his prayers at the mosque since he could not do them all while he was working.
The mosque in question was a makeshift adjunct to a hostel for North Africans in Buttes Chaumont.
The self-proclaimed imam there was a charismatic 22-year-old French Algerian called Farid Benyettou who, despite being barely out of his teens, exercised a powerful influence over many of the local young Muslims.
Three of his acolytes went to Iraq and died while carrying out suicide missions.
Barbara knew little about Benyettou except he was gradually taking Peter away from her.
Farid Benyettou is awaiting trial, following his arrest in 2005
Soon Peter swapped his cool street gear for Islamic dress.
Going to the cinema and restaurants, which they had always enjoyed doing, was out.
So was sex.
"What bothered him was that we had an intimate relationship out of wedlock," she said. "So I said if that's the only thing that's bothering you, we could stop."
But for Peter that was not enough.
Soon, touching each other, kissing and holding hands was ruled out.
Again, Barbara did not fight it as she loved him.
Peter was told he could never be alone with Barbara
They spent hours talking on the phone until Peter told her that his "professor" had told him it was forbidden if Peter was alone.
They then carried on their relationship over the internet, until that too was vetoed.
Peter was told he could never be alone with Barbara.
"First we sat at the table next to each other, then he moved to the sofa, then a bit further away. He moved away from me progressively."
Barbara even offered to convert to Islam but Peter rejected the offer.
In May 2004, Peter said he was going to Syria for a few months to have a holiday, learn Arabic and study Islam in greater depth.
His mother, to whom he was close, gave the trip her blessing on condition he kept in regular touch.
At first he was true to his word via an internet cafe in Damascus, until he said he was going to a village with no internet access.
There was silence for several months.
One day in November, the phone rang.
It was Peter, although he never said where he was calling from.
When he hung up, Barbara checked the country code on the internet and discovered he was in Iraq.
That was the last Barbara heard until the Ministry of Foreign Affairs telephoned and said they had been informed by the US authorities that Peter had been arrested on 2 December, 2004, in Falluja - around the time of the American onslaught.
The caller told Barbara that Peter had no ID. At first he had been held in a local detention camp and then transferred to Abu Ghraib prison in August 2005.
Last July, she learned that Peter had been sentenced by an Iraqi court to 15 years in gaol.
I asked how she felt about those who had led Peter down the road to Jihad.
"I'm furious. They took advantage of him. His youth was wasted, his life was wasted and my life and his mum's life were wasted.
"When he comes back, I don't know if I'll hug him or hit him." Barbara will have a long wait.
Talking to terrorists
Five years on from the 11 September attacks, despite some significant victories, the "war on terror" is far from won.
Although the nature of the current global threat is unprecedented, historically governments have negotiated with terrorists they swore they would never talk to, from the IRA and Eta to the PLO and the ANC.
So is it time to talk to al-Qaeda?
According to General Ali Shukri, former counter-terrorist adviser to King Hussein of Jordan, it is not something that should be ruled out.
"There is no harm in talking," he told me.
"Engagement is not endorsement. Are the Americans prepared to wage war for the next 25 years?"
Few in America would agree.
"We don't talk to terrorists, we put them out of business," is the White House position.
One person who does agree with General Ali Shukri is the Harvard academic, Professor Mohamed Mohamedou.
"At some point we should create a space for a cogent, rational discourse that thinks outside of this box. Responsible leadership calls for a more nuanced understanding," he told me.
But there are very few takers.
US foreign policy
Although no-one is seriously thinking about MI6 or CIA setting up back channels to Osama bin Laden's cave, perhaps it is worth paying some attention to what he has been saying for the past 10 years.
His statements are not about any Caliphate, a pan-Muslim state which is rarely mentioned, but about US support for Israel, its backing for "apostate" Arab regimes in the Middle East and the presence of US troops in Muslim lands.
In reality, the issue is US foreign policy.
In the words of Mike Scheuer - who headed the CIA's Bin Laden Unit before and after 11 September, 2001, and who warned his superiors about the consequences of invading Iraq - "the only indispensable ally bin Laden has in terms of generating a worldwide Jihad is US foreign policy. Without that, his task is almost insurmountable."
In a year's investigation, I found the tragedy of Barbara and Peter replicated across Britain, Europe and the Middle East.
I was left in no doubt from all those I spoke to that Iraq above all else was the motivating factor behind the radicalisation and recruitment of young Muslims, and that the US-led invasion has gifted Osama bin Laden with a Jihad he could only dream of.