A teenager suspected of being the Parsons Green bomber had been spoken to by police a number of times, neighbours of his foster family claimed today, amid questions over what authorities knew.

The 18-year-old refugee, believed to be Iraqi, was a "problem" to foster parents Penny and Ron Jones and they had been contacting officials saying that they were unable to cope, it was said.

Neighbours of their house in Sunbury-on-Thames, south west London, said that he had been brought home by officers just two weeks before the attack and they regularly saw plain clothes officers at the property.

The teenager was arrested at the Port of Dover on Saturday morning on suspicion of planting the home-made bomb which partially detonated on a District Line train on Friday morning, injuring 29 people.