A theme park was fined £250,000 after a teenage girl died after plunging 100ft from a ride.

In 2004, Hayley Williams, 16, from Pontypool, died after falling from the Hydro Ride at Oakwood, Pembrokeshire.

A court heard today how hundreds of lives were put at risk on a white knuckle ride from which a teenage girl fell to her death. Staff at the theme park failed to carry out vital safety checks in the week leading up to the tragedy.

Sunday school teacher Hayley Williams, 16, plunged from the top of the Hydro ride as it began an almost vertical descent from 100 feet up in April 2004.

The accident happened at the Oakwood theme park, near Narberth, in West Wales.

A High Court judge listened to a graphic description of the moment the teenager fell to her death today at a sentencing hearing at Swansea Crown Court.

Oakwood Leisure Ltd admitted a single charge of failing to ensure persons not in its employ were not exposed to risks to their health and safety, at a hearing back in July.

Mark Harris, prosecuting for the Health & Safety Executive, said: "At about 3.40pm on April 15 2004 Hayley Williams, aged 16, was ejected from the Hydro ride at Oakwood theme park, Canaston Bridge, Narberth, Pembrokeshire.

"She fell approximately 100 feet and later died from injuries sustained in the fall.’’ He said that in the days after the tragedy HSE inspectors closely analysed a week's worth of CCTV footage at the ride to gauge how staff carried out safety procedures.

Over the period more than 4,000 people used the ride and the recordings revealed that on average 29.2% did not have their safety restraints tested.

The court had heard that a safety T-bar and an airline style belt had to be used by all passengers.

Staff monitoring the ride were instructed to push down on the safety T-bar and pull up on the belt to ensure both were properly secured.

But the recorded footage revealed that on the worst single day in the week before the tragedy 87.8% of restraints were not tested at all.

The same footage also revealed that staff safety checks were completely neglected in the case of Hayley Williams.

None of the 23 passengers in the "boat’’ in which she was travelling had had the vital checks either.

It is also unknown whether she actually put on the secondary safety belt before the ride set off.

Proshant Popat, for the defence, told the court: "It came as a considerable shock to those in positions of management in the company to see what they saw on the footage.

"It is that which led to the plea being entered,’’ he added.