The bus was carrying 72 children when it crashed

Inspector Andy Germain said that although the steering wheel was taken from the vehicle as evidence at the time of the crash, until the inquest hearing opened, the wheel had never been examined by fingerprint experts.

Stuart Cunningham-Jones died and 30 Cowbridge Comprehensive school pupils were hurt on the bus which careered off the road and hit a tree near the village of Ystradowen in the Vale of Glamorgan, in December 2002.

On Thursday, the court was told that a child grabbed the steering wheel - seconds before it crashed into a tree, killing Stuart.

The police officer told the hearing that he could only apologise about the steering wheel.

Stuart Cunningham-Jones was sitting on the top deck of the bus

He said that a request had been made to the boy's solicitor for a set of prints but they could only be taken now on a voluntary basis.

In June last year the CPS decided there was insufficient evidence to charge anyone in connection with the crash.

Also giving evidence on Friday, Terry Cooper, director of operations at the EST bus company, said he had requested an escort on the bus service S19, but was told there were insufficient funds.

"My personal opinion is that an escort should be provided for troublesome groups but where the escort is sourced from is a problem because of whether or not the escort would have any authority to do anything about unruly behaviour," he said.

"A driver has no authority whatsoever to put children off the bus."

Giving evidence on Thursday at Cardiff Coroner's Court, driver Reginald Davies broke down in tears as he explained that he stopped the bus once because some pupils' behaviour was becoming dangerous, that children had been fighting close to his cab.

Reginald Davies said he could not have avoided hitting the tree

"For a split second I did not realise it was an arm on the steering wheel, I just thought something had happened with the bus because I could not turn the steering wheel," he said.

"He was grabbing the wheel to stop himself falling, I believe."

Earlier in the week, a 14-year-old pupil said he was standing near the baggage rack of the bus when he saw another pupil distract the driver up to 10 times.

Before witnesses began giving evidence, Coroner for Cardiff and the Vale of Glamorgan Lawrence Addicott told the jury of seven men and three women, that no one was "on trial" and there were no sides.

Stuart, a pupil at Cowbridge Comprehensive School, was sitting on the top deck of the service bus when it left the road.

The inquest jury have been sent home for the weekend and the hearing will continue on Monday.