Alton Towers will remain closed for a second day today amid reports that one person lost a leg in a rollercoaster accident.
The Health and Safety Executive is investigating the crash which left four people seriously injured and 16 people trapped on the £18 million Smiler ride.
Two men and two teenage girls suffered serious leg injuries when the carriage they were travelling in hit a stationary one on Tuesday.
Some passengers were left trapped 25ft in the air for more than four hours.
Nick Varney, chef executive of Merlin Entertainments, which runs the park, said: “The safety of our visitors is our primary concern. The park will remain closed until we understand better the cause of this dreadful incident.
“I would like to thank the emergency services for their swift and effective response – they were outstanding.
“A full investigation is now under way and we will continue to work closely with the emergency services and the Health and Safety Executive to better understand the cause of this terrible accident.”
He added: “Technically what happened is impossible and should not have happened.
“Rollercoasters are designed so you do not have two cars on the same path of the track and obviously two were because that’s what happened. So we need to look into that very quickly and closely.”