London, Dec. 27 (ANI): Five years prior to the recently foiled bid by a London student to bomb a Detroit-bound trans-Atlantic flight, two British security experts had estimated that at least 31 British colleges were bases for known extremists.

Professor Anthony Glees and Chris Pope of Buckingham University’s Centre for Security and Intelligence Studies had reported their findings in 2005, News of the World reports.

On Saturday, Glees said: “The tutors of these students have to look out for signs of radicalisation.”

“People do not become terrorists at the flick of a switch. It’s a process of brainwashing and it should be detectable,” he added.

He warned that even the latest technology cannot stop increasingly sophisticated terrorists from blowing up planes.

“However smart we are, al Qaeda tries to be even smarter,” he pointed out.

US Visa records list Nigerian origin Abdul Mutallab, 23, as a mechanical engineering student from University College London in the city dubbed “Londonistan” by Washington commentators because of repeated links to global terrorism. (ANI)