People with mental disabilities are not only easier to manipulate but also less likely to arouse suspicion and if they are white Muslim converts, they are even less likely to be noticed in Britain, according to them.
"It is a grotesque concept but they are using people who are clearly mentally subnormal. We know they have clever radicalisers who will take advantage of anyone they think they can manipulate, whether they have an IQ of 60 or 140," an MI5 counterterrorism official told The Sunday Times.
According to him, the case of Nicky Reilly, who was held over a nailbomb attack last week in Exeter, is one such example. A 22-year-old Muslim convert, Reilly is said to have been suffering from Asperger's syndrome -- a form of autism.
Other security officials claim that Osama bin Laden's terror network al-Qaeda has exported the tactic of targeting mentally challenged people from Iraq, where disabled ‘foot soldiers’ are being used to devastating effect.
They point to a case in February when a suicide bomber in a wheelchair killed an Iraqi general in Samarra, north of Baghdad. Earlier, two women, initially thought to have Down's syndrome, acted as couriers for a bomb in Baghdad, killing over 100 people.