A British Muslim convert with a mental age of ten was unable to blow up a restaurant because he'd locked himself in a toilet.
Nicky Reilly, 22, had gone into the cubicle of an Exeter eaterie to assemble the nailbombs from chemicals in bottles. He then planned to rush among the 50 diners - many of them children - and detonate the devices.
However, he found he couldn't unfasten the lock and then one of the bombs exploded, setting the others he was holding off.
Reilly, who was groomed over the internet by extremists into becoming a suicide bomber, was arrested when he staggered outside with serious facial injuries.
Prosecutor Stuart Baker said: 'He was unable to open the lock of the cubicle door and come out, by which time the first device had already exploded.'
Anti-terror investigators believe Pakistani radicals targeted Reilly because of his history of mental illness.
The case is a chilling echo of terrorist methods in Iraq, where the disabled have been persuaded to blow themselves up.