The black and burgundy bag had been among luggage on the train on Thursday. It contained 15lb of Semtex as well as enough triggers and timing devices to make six bombs. As a single bomb, that amount of high explosive could wreck a hotel or conference centre.
The 31-year-old thief, who is unemployed and has convictions for petty crime, had snatched the bag at random, hoping it would contain valuables. The man had picked up and opened one of two cardboard boxes in the holdall which contained blocks of Semtex.
Last night he was under police protection, and his family said they feared he could become a target for the IRA.
The man snatched the bag on Thursday and took it to a housing estate in Reading where he lives, opened it in the street and panicked when he saw the contents. He threw it away, causing streets and houses within a half-mile radius to be evacuated for six hours.
Detectives say the terrorist or gang may have had other luggage with them on the train. The holdall was with other bags, possibly two or three, on the floor near luggage racks close to a toilet in one of the carriages, the thief has told police.
Scotland Yard's Anti-Terrorist Squad has shown the man file pictures of suspected terrorists to see if he recognises any faces. One possible suspect is a woman.
The train left Manchester at 8.17am, stopped at Stockport at 8.24, then at several other stations. The bag snatcher joined the train at Oxford at 11.24. He took the bag as he left the train at Reading at 11.54.
Police hope many of the 200 people on the train will come forward to describe other passengers.Reuse content