Nicky Reilly’s attempt to detonate a nail bomb in an Exeter restaurant represented a new development in the terrorist threat to Britain. In the terror plots here between 2004 and 2006 the operatives were largely British Pakistanis and had been trained at camps in Pakistan run by al-Qaeda or its allies. After their discovery, the monitoring of young men travelling to Pakistan was stepped up and a much more hostile antiterrorist environment was created in Britain.

As a result, there has been a significant lull in “attack planning” by groups with direct al-Qaeda links. However, in its place is emerging a phenomenon best described as “al-Qaeda-inspired” activity. Reilly falls into this category and, although he was not a very capable terrorist, he presents the authorities with a worrying problem. He was radicalised from afar and, because of his mental illness and vulnerability, was easy prey for those who manipulated him. They taught him online how to make bombs and discussed potential targets with him.

Reilly lived in Plymouth, not a city associated with extremism, and although the mosque he attended once figured in a surveillance operation, he was not on the intelligence radar. He was almost undetectable and, had he not been inept, could have killed and maimed.

The hope is that such loners will be rare creatures. But the internet jihad is developing fast and is hard to combat. According to the respected Jamestown Foundation, the net has become “the easiest and safest way . . . to reach young militants, who likely lack training, and steer them under al-Qaeda’s general command”. Reilly was one of those and there could well be others, all of them just as hard to spot and stop.

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