A SAFETY investigation was under way last night into a rollercoaster accident at one of the region's most popular tourist attractions, after a woman was left fighting for her life.

The 20-year-old, who is thought to have been thrown from a car on the ride, suffered severe head and spinal injuries at Lightwater Valley theme park, near Ripon, North Yorkshire.

She was one of four people taken to hospital after the accident on the white-knuckle ride.

A team from the Health and Safety Executive arrived at the park last night and the Treetop Twister ride - which was opened in a blaze of publicity only a month ago - was immediately shut down.

The ride is likely to be closed for several days until investigations are completed, although the rest of the theme park will stay open.

The accident happened at about 1.45pm yesterday as the park was packed with thrill-seekers when two cars on the ride ran into each other.

The victim was airlifted to Leeds General Infirmary, where her condition was described as serious.

Two men, in their early 20s, are believed to have been thrown forward into the safety bars of a car on the ride.

They were taken to Harrogate District Hospital with abdominal injuries. One is also thought to have a broken arm. A third man needed hospital treatment for whiplash injuries.

Ambulance service spokes-man Nigel Metcalfe said the woman was understood to have been thrown from her car onto the track. She was then struck by other cars following behind.

"Ambulance crews from Ripon and Harrogate were at the scene to stabilise the lady and we called in the Yorkshire Air Ambulance to transfer her to Leeds," he said.

A shocked witness said last night: "There were two carriages smashed together and people were there talking to the passengers who were holding on to their arms and their ribs."

The Treetop Twister - described as "a hair-raising cross between a rollercoaster and a waltzer" - was opened to public fanfare last month by girl band The Honeyz.

The ride involves cars, seating four adults, travelling at high speed up and down a track. Fairground managers say passengers experience three Gs of force during the ride.

Lightwater Valley manager Dudley Westgate said: "Two cars shunted into each other, one going into the back of the other. Anything like that is devastating. This was a brand new ride, it was installed in May, fully commissioned and fully certified."

He said: "Lightwater Valley has operated for over 20 years with an excellent record of safety. All of the staff and management are deeply concerned for those injured in this incident."

A Health and Safety Executive said last night: "We have got two people on the site now. One is a specialist and they are going to be there for quite some time. We just don't know the cause at this stage.

"It seems very complicated but our people will be there for the best part of tonight and return tomorrow morning."

The issue of safety at leisure parks has been raised several times in recent years.

In June 1994, passengers on The Ultimate at Lightwater Valley - then the world's largest rollercoaster - were showered in blood when a deer ran into its path and had its legs ripped off.

A 12-year-old boy was taken to hospital as a result of the accident.

In July the same year, a man collapsed and died after riding the Nemesis at Alton Towers, Staffordshire, although bosses said there was no definite link between the ride and his death