Alton Towers [owned by Merlin Entertainments] has been closed while an investigation continues into a "dreadful" rollercoaster accident that left four people with serious injuries. Two carriages crashed on the Smiler ride at the Staffordshire theme park on Tuesday, leaving some passengers trapped for four-and-a-half hours. Two men, 27 and 18, a woman, 19, and a girl, 17, have suffered serious leg injuries. Bosses have announced that the park will also be closed on Thursday. The BBC's Danny Savage said it was understood some of those on the ride sustained "life-changing injuries".