Four teenagers have been seriously injured after an Alton Towers rollercoaster carriage carrying 16 people crashed into an empty carriage.
The accident happened yesterday on the Staffordshire attraction’s 50mph Smiler ride.
Two male and two female teenagers suffered serious leg injuries in the crash, while the other 12 occupants required triage.
A ramp was built to help emergency services reach the occupants of the ride, who were around 25 feet up in the air at an angle of around 45 degrees.
The £18 million rollercoaster, which boasts a record-breaking 14 loops, has been closed twice due to safety concerns since opening two years ago.
Alton Towers owner Merlin Entertainments was the biggest faller on the FTSE 100 after the crash, with its shares down 3 per cent. Visitors to Alton Towers reported on social media that the ride had broken down.
Lucy Farrugia tweeted: “Smiler broke down when I was on it this morning and now it’s crashed. Hope everyone on it is OK, saw air ambulance arrive.”
Sophie Underwood, who was waiting to board the ride, told the BBC: “They had made quite a few announcements to say there were technical difficulties. They were sending coaches around with nobody on them.
“And then they said they had sorted it out so they decided to put people on the coach.”
Ms Underwood described a carriage carrying passengers crashing into another that was stationary at the top of the ride.
“It was quite scary. There was a big crash and as soon as everybody heard the crash everybody started walking back and leaving the ride,” she said.
Four air ambulances rushed to the scene together with four ambulances and paramedics. Staffordshire Fire and Rescue said it had sent four pumps, a rescue tender, rope rescue and an aerial ladder to the incident.
Danny Simm, a musician, who witnessed the aftermath of the accident, said a number of people appeared badly injured.
He tweeted: “People unconscious, knocked out. Blood everywhere. It really was shocking. Air ambulances landing now, people still stuck.”
Alton Towers says the Smiler features “a series of twisted psychological effects including optical illusions, blinding lights and near-misses designed to mess with your mind”.
In July 2013 it was closed after reports a bolt was seen to have fallen from the ride and that November was shut after plastic guard wheels came loose and hit front row riders.
Sixteen journalists were left stranded for around 30 minutes during a preview in May 2013. They were left dangling after the rollercoaster ground to a halt at a 50 degree angle.
An Alton Towers spokeswoman said during the aftermath: “The emergency services, including the air ambulance, are now in attendance and are assisting resort staff as they work to evacuate those 16 people still on the ride. We can confirm four guests have sustained serious injuries, and they are being treated at the scene until they can be evacuated. There will be a full investigation.”