He took it home and opened it, hoping to find valuables inside. When he saw the wires, detonator and explosives, he panicked, ran outside and dumped the case in Basingstoke Road, Reading. A man was being questioned by police last night.
Thousands of commuters and shoppers were cleared from the area for more than six hours while an army bomb disposal team and the Scotland Yard Anti-Terrorist Squad were called in. Ron Clark, 66, who lives close by, said: 'My son and his two mates were walking down the road when this bloke ran past them shouting, 'It's a bomb, it's a bomb.' '
The manager of a shop called the police, the area was sealed off, and 230 homes evacuated while the bomb was made safe, Thames Valley police said. It is understood the device had not been primed.
Superintendent Peter Hanks, head of operations for the Reading police area, said: 'The items in the bag are under analysis. We have been in contact with the Anti-Terrorist Squad but I am prepared to say no more at this stage as it is still very much a live incident.'
A train believed to have been used by the bomber had been taken out of service to be examined by forensic scientists at Basingstoke. A police spokeswoman said: 'We are 99 per cent sure that the person who was originally carrying the package was travelling by train.'
The IRA was thought to be responsible for two bombs at Reading station last October. One exploded a few hundred yards from the station, and another had been found earlier in a lavatory.
No group claimed responsibility for yesterday's device.