FOUR people have been seriously injured in a collision between two carriages on Alton Towers amusement park's Smiler rollercoaster.

The accident, at around 2.09pm, involved two carriages - one containing 16 passengers and the other empty - which came together on a low section of the track.

A West Midlands Ambulance Service spokeswoman said: "There are 16 patients on board The Smiler requiring triage, four of which have reported serious injuries.

"Ambulance staff and medics are working quickly with resort staff to gain access to the seriously injured."

Visitors to Alton Towers reported on social media that the ride had broken down earlier today.

Lucy Farrugia said: "Smiler broke down when I was on it this morning and now it's crashed. Hope everyone on it is OK, saw the air ambulance arrive."

Danny Simm, a musician and songwriter who is also a radio presenter on 96.5 Bolton FM, who witnessed the aftermath of the accident, said that a number of people appeared to be badly injured.

He tweeted: "People unconscious, knocked out. Blood everywhere. It really was shocking. Air ambulances landing now, people still stuck."