Euston station evacuated briefly after small explosion caused by e-cigarette - police

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.Britain is on high alert after a series of militant attacks in London and Manchester this year that have killed 36 people.Earlier on Tuesday, Liverpool airport was evacuated and passengers kept on their planes while a bomb disposal team dealt with a suspicious package.