Four people needed hospital treatment and 25 others were injured after two rollercoaster carriages crashed into each other at a Midland theme park yesterday.

The Runaway Mine Train at Alton Towers, in Staffordshire, carries up to 46 people and was full to capacity when the accident happened at 11am.

A park spokeswoman said everyone on the ride was evacuated and the ride was clear within 40 minutes.

A group of community first aiders with Staffordshire Ambulance Service were taking part in a training exercise at the park and helped the injured.

Two women, aged in their late 30s or early 40s, were airlifted to the University Hospital of North Staffordshire in Stoke-onTrent suffering possible whiplash, spinal or abdominal injuries.

Staffordshire Ambulance Service said the rest of the casualties were taken to an on-site medical centre where a doctor decided that a third woman should attend the same hospital for a check-up. She was conveyed by land ambulance.

A fourth person, a man, is believed to have made his own way to a minor casualties centre in Leek.

Last night the ride remained closed as Health and Safety Executive inspectors and the park's safety officials carried out an accident investigation.

Billed as a "starter rollercoaster", the ride reaches a top speed of 20mph, as the speeding train careers "out of control" along a rickety track and under make-shift mine shafts.

The 12-carriage train split into two sections after a coupling fell out as it approached a tunnel, then the front half rolled backwards into the rear carriages.

Staffordshire Ambulance Service spokesman Bob Lee said: "These are the sort of injuries we expect to see in a car accident, but it could have been a lot worse.

"We actually had a group of community first responders on a training exercise in the park at the time, and they were on the scene within five minutes.

"I have to give full marks to Alton Towers and their medical centre team, who were excellent and flooded into the area within minutes."

An Alton Towers spokeswoman could not confirm whether those injured on the ride were with a school party but said there were 300 coaches of school children and teachers in the park yesterday.

She said: "The ride has been closed and will remain so whilst a thorough investigation is carried out by the park's management team together with the Health and Safety Executive."

The rest of the theme park will remain open, but it is not known whether the Runaway Mine Train will reopen today.