The bomber who tried to kill hundreds of airline passengers on Christmas Day fostered a worldwide network of radical Islamist contacts while studying in London, the Observer has learned.
Counter-terrorism detectives are examining "e-mail and text traffic" involving Umar Abdulmutallab, the Nigerian-born bomber. They have found that he has been in contact with jihadists from across the world since 2007.
The disclosure comes as Gordon Brown today announces a joint US plan to fund an anti-terror police unit in Yemen, where the bomber is believed to have received al-Qaida training in the use of explosives.
Meanwhile, police and intelligence officials are piecing together how Abdulmutallab, 23, had been transformed in five years from a well-to-do engineering student into a would-be al-Qaida suicide bomber. Whitehall officials believe his views were hardened over a three-year period from 2005 when he was studying engineering at University College London, where he was president of the Islamic Society in 2007.
"It is becoming clear that he had very close contacts across Europe and Africa, some of whom had extreme views," said a senior Whitehall source. "There is no evidence of criminal activity, but there is evidence that he held extreme views and was in contact with those who had such views as long ago as 2007. The US authorities are aware of this, and are anxious to trace all of his contacts. We don't know where he was first cultivated as a possible terrorist, but he was politically involved in Britain." Security service sources insist that the "crucial" period in his radicalisation appeared to be the six months he spent in Yemen.
Abdulmutallab, the son of a wealthy Nigerian financier, tried to detonate explosives sewn into his underpants as the Northwest Airlines jet flew over the United States. He was stopped by fellow passengers.
British police are known to be concentrating on his time at UCL. They are believed to have sought access to computers, and have contacted former members of the Islamic Society.
Emails that Abdulmutallab had written when he was a 19-year-old student emerged last week, in which he appeared to admit to having "jihadist fantasies".
In one, he wrote: "I won't go into too much details about me [sic] fantasy but basically they are jihad fantasies. I imagine how the great jihad will take place, how the Muslims will win, God willing, and rule the whole world and establish the greatest empire once again!"
A former friend of Abdulmutallab said he believed he was radicalised after leaving the UK in 2008. Qasim Rafiq, who was also involved in UCL's Islamic Society, said he had shown no signs of violent extremism, but had cut himself off from friends a month after leaving university. "When I heard the news I wasn't sure what to think. I thought: could this really be the same person?" he told the BBC. British concerns will concentrate on his time in the UK, where Abdulmutallab cultivated his views. Up to a dozen universities, including UCL , are believed to have been identified by counter-terrorism officials as of "concern" at the time he finished his studies in London.
Assessments by the Joint Terrorism Analysis Centre are believed to have cited UCL in 2008 as one of up to 12 universities that might have a problem with "extremism".
Abdulmutallab, who was remembered by lecturers as a quiet and polite student, is believed to have received military training in the Yemen in the five months before the attack. In October, he made a rare telephone call to his home, during which he said it would be their "last contact". The call so alarmed his father that he warned the authorities in Nigeria, as well as the CIA, that his son may have come under the influence of Islamist terrorists.
Recordings of Anwar al-Awlaki, an al-Qaida sympathiser who is believed to have inspired Abdulmutallab in Yemen, can be bought through British-based websites and bookshops. Three shops in London and Manchester were contacted by this newspaper last week. Staff said they could sell DVDs of the speeches by the cleric, who is banned from the UK.
As recently as last April, students at London's City University Islamic Society's annual dinner were invited to hear the words of al-Awlaki being broadcast live into Britain.
Alexander Meleagrou-Hitchens, a research fellow for the think-tank the Centre for Social Cohesion, said that al-Awlaki has become an increasingly influential figure. "For well over a year now, organisations such as ours have repeatedly warned about the dangerous influence of this man, with most of our warnings falling on deaf ears," he said.
"They had no objection to his giving a video sermon to a gathering at Kensington and Chelsea town hall. We are also often told that, although al-Awlaki's views may be unsavoury, he has never been convicted of any crime. Clearly, this excuse is simply not good enough."
Downing Street and the White House have agreed to intensify joint British-America work to tackle the emerging terrorist threat from both Yemen and Somalia in the wake of the failed terror plot, Brown will announce today. Among the initiatives he has agreed with Obama is a US-UK funding for a special counter-terrorism police unit in Yemen.
The prime minister and president believe that a larger peacekeeping force is required in Somalia and will support this at the UN Security Council.
The PM has also asked that the emerging threat from Yemen and Somalia be placed on the agenda for the January EU general affairs council.
Brown has also called a special meeting of the ministerial committee on national security, international relations and development to discuss further the UK's response to last week's attempted attack. The committee includes security and military chiefs.
Yesterday, Obama accused an offshoot of al-Qaida over the alleged Christmas Day bomb plot to blow up the Northwest Airlines jet. He said it appeared that Yemen-based al-Qaida in the Arabian Peninsula had armed and trained Abdulmutallab. Obama has already condemned lapses that allowed the accused, who was on a terror database, to board the jet.