An X-ray picture shows a bomb packed with nails, which was found in a car near Luton railway station in July 2005. The picture was first obtained by US broadcaster ABC News.

Police said the car containing the explosives, which was found five days after the 7 July attacks, was left by the bombers when they boarded a train at Luton. (ABC News picture).

The discovery initially prompted police fears that a second suicide gang were preparing an attack. (ABC News picture)

Police said the devices could have caused deaths on a similar scale to 7 July. (ABC News picture)

A series of controlled explosions were carried out by police following the discovery. (ABC News picture)

Among the find was what were said to be a number of detonators (ABC News picture)