British police evacuated London’s Euston station on Tuesday after a small explosion, most probably caused by an e-cigarette in a bag, prompted a lock-down and sent dozens of armed officers racing to the scene.

“Officers are currently at Euston station responding to a security alert. We are investigating but there appears to have been a small contained explosion which is believed to have been caused by an e-cigarette which was in a bag at the station. No one  is believed to have been injured. The station is currently evacuated whilst officers and search dogs check the area is safe,”  the British Transport Police said in a statement.