The security services knew three years ago that the Detroit bomber had “multiple communications” with Islamic extremists in Britain, it emerged this weekend.
Counterterrorism officials said Umar Farouk Abdulmutallab was “reaching out” to extremists whom MI5 had under surveillance while he was studying at University College London.
Officials said the 23-year-old Nigerian was “starting out on a journey” in Britain that culminated in his attempt to bring down flight 253 as it prepared to land in Detroit, Michigan, on Christmas Day.
None of the information was passed to American officials, which will prompt questions about intelligence failures prior to the attack.
British officials have now passed a file to their US counterparts on Abdulmutallab’s activities in Britain while he was a student from 2005 to 2008. It shows his repeated contacts with MI5 targets who were subject to phone taps, email intercepts and other forms of surveillance.
Intelligence officials have defended their decision not to flag Abdulmutallab as a possible terrorist risk. They say he was one of many youths who mix with extremists, but are not themselves thought to be involved in plotting or supporting terrorism.
A senior Whitehall official said the intelligence agency had conducted a quick assessment of Abdulmutallab while he was living in London and concluded that he was not a threat to national security.
“There had to be a judgment made depending on the nature of the relationship as to whether there was any threat,” said one official. “Someone will have judged: okay, [he is] noted but if there was no evidence of a threat, [they would] move on.”
British officials believe Abdulmutallab was recruited to undertake the Detroit plot after he left Britain, most probably while he was in Yemen last summer. Up to a dozen young British Muslims are thought to be engaged in terrorist training there, according to officials.
While in Britain, Abdulmutallab attended a mosque in Goodge Street, central London, which is run by the Muslim World League, a Saudi-based organisation. The league promulgates a fundamentalist interpretation of Islam, but has repeatedly condemned terrorism.
One of the radical preachers believed to have inspired Abdulmutallab is the American-born cleric Anwar al-Awlaki, who is based in Yemen and is believed to have inspired several terrorist cells in Britain and the United States.
The Sunday Times has established that Abdulmutallab first encountered Awlaki while he was studying Arabic in Yemen in 2005.
US intelligence officials are now investigating the scale and nature of contacts between the two men.
Britain and the US are to jointly fund a counter-terrorism police unit in Yemen along with more support for the Yemeni coastguard. Downing Street said Gordon Brown and President Barack Obama had agreed the move as part of the response to the failed Detroit plot. The two countries will also be pushing for more UN intervention to tackle the emerging terrorist threat in Somalia.
Mr Brown will hold talks with ministerial colleagues and intelligence advisors this week, and the initial findings of a review of security at UK airports — ordered in the wake of the Detroit incident — will be delivered “in days”, according to Downing Street