Two journalists arrested while trying to plant a fake bomb on a freight train have been released on bail.
The Daily Mirror reporters were arrested at the Stonebridge Park depot, in north-west London, after they were seen acting suspiciously by staff.
A Mirror spokesman said the stunt was a justified follow-up after its journalists managed to place a fake device on a nuclear train in 2006.
Police said two men, aged 32 and 51, had been bailed until 7 September.
British Transport Police said the men, one from north London and the other from Surrey, were arrested on Tuesday following a report of trespass.
The Mirror spokesman said it followed an incident last year in which journalists succeeded in planting a fake bomb on a nuclear train, which highlighted serious security lapses.
"We are happy to see that the security procedures have now improved," he said.