Two British newspaper journalists were arrested on Tuesday after trying to plant a fake bomb on a train to test security, the publication and police said.
The unnamed pair, both men working for the Daily Mirror tabloid, were detained Tuesday afternoon at the Stonebridge Park depot towards the end of the Bakerloo London Undeground line in the north-west of the British capital. Railway staff alerted British Transport Police after catching them carrying their "bomb" on the premises.
A Daily Mirror spokesman said their actions were a "legitimate and justified journalistic exercise" because last year they had attempted and succeeded in planting a fake bomb on a nuclear train, highlighting serious security lapses.
"We therefore felt that it was a legitimate and justified journalistic exercise to repeat the action in the interests of public safety. We are happy to see that the security procedures have now improved," he added.
A police spokeswoman confirmed two men had been arrested at the depot on suspicion of trespass and were taken to a nearby police station. A search was carried out but the men had not yet been charged with any offence.
The Daily Mirror has a history of exposing security lapses: in January a journalist managed to plant a fake bomb on an unguarded train in sidings, which was reportedly packed with military explosives.
It ran a similar expose involving trains carrying nuclear waste to a reprocessing plant six months earlier. But its most infamous scoop came when a reporter managed to get a job with bogus references as a footman at Buckingham Palace, Queen Elizabeth II's official London residence.
In 2005, a reporter of The Sun tabloid claimed to have driven a van containing a brown box with the word "bomb" written on it within yards (metres) of the queen's private apartments inside Windsor Castle, west of London.