A man accused of carrying ammunition on a flight from Washington to London was arrested tonight on suspicion of terrorism offences.
The 45-year-old Sudanese-born passenger was taken from Heathrow to a central London police station to be quizzed by anti-terrorist branch officers.
The passenger was initially held for allegedly carrying bullets as he went through a routine security check in transit to boarding a connecting flight to Dubai.
Scotland Yard said he was later arrested under section 41 of the Terrorism Act 2000, which refers to the alleged involvement in the commission, preparation or instigation of acts of terrorism.
He had not been picked up by security at Washington's Dulles airport, where he boarded Virgin flight VS022.
The man was missed there despite the route between London and Washington having been publicly identified as a potential target for terrorists in recent weeks.
Over the festive period there was repeated disruption to British Airways' London to Washington BA223 service and it was cancelled three times amid terror fears.