The truck driver and two adults travelling with the children were also hurt in the accident, near Tewkesbury, Gloucestershire.
Yesterday's crash reopened the debate on whether school buses should be fitted throughout with seat belts - only the mini-bus driver and front passenger had restraints. Police say the accident occurred as the six boys and three girls aged between 5 and 14 were being driven to Alderman Knight special school in Tewkesbury. It helps children with moderate learning difficulties.
The mini-bus collided with the truck on a straight stretch of road near Ford. It then turned on its side and ploughed through a stone wall, trapping Richard Jones, six, of Aston Magna, near Moreton-in- Marsh, Gloucestershire. He was dead on arrival at Cheltenham General Hospital.
The other eight pupils, several of whom had to be cut free from the wreckage, were also taken to the hospital for treatment. They were detained overnight for observation, as were their adult supervisor, Huw Morgan, 50, and the mini-bus driver, Martin Rose, 36.
Paul Wilson, the hospital's accident and emergency consultant, said some of the injuries could have been prevented had all the children been wearing seat belts.
The driver of the pick-up truck, Gareth Heath, 41, of Cardiff, was cut free and flown by air ambulance to the John Radcliffe Hospital in Oxford with serious spinal and internal injuries. He was yesterday described as stable.
Pupils at Alderman Knight were told of the accident in assembly, and were offered the chance to see a psychologist trained in bereavement counselling. A spokeswoman for Gloucestershire County Council confirmed that the mini-bus had front seat belts only. Carol Rose, mother of the driver, said it had recently passed its annual Department of Transport inspection.
Concern over the safety of school buses has grown since last November, when 12 children and their teacher died on the M40 in Warwickshire after their mini-bus struck the back of a lorry and burst into flames. A few days later, 13 members of a school football team were injured when their mini-bus was crushed between a petrol tanker and a lorry on the A3 at Paines Hill, Surrey. Doctors said all but one of the pupils escaped serious injury because the vehicle was fitted with seat belts, which they were wearing.
The Department of Transport said yesterday that seat-belt regulation is a matter for European Union law, and while Britain could act alone, legislation would be difficult to enforce. A European Commission working group has been formed to examine bus and coach safety.
However, motoring organisations, the Royal Society for the Prevention of Accidents and other pressure groups believe seat belts should be fitted now to all minibuses and coaches.
Derek Prentice, assistant director of the Consumers' Association, yesterday called on Robert Key, the Minister for Roads and Traffic, to act without waiting for Europe- wide agreement. 'Research consistently shows that seat belts save lives. Legislation which makes the fitting of seat belts in mini-buses and coaches compulsory is long overdue,' he said.
His view is supported by David Young, Labour MP for Bolton South East, who has tabled Commons questions to John MacGregor, Secretary of State for Transport, and John Patten, Secretary of State for Education, demanding that all coaches used to carry children should have seat belts for each passenger.
However, Christine Milburn of the Bus and Coach Council, said the Government and the European Commission must first complete thorough safety studies. 'We have to make sure we have the right system for the job. Once the research is done and our members are told, 'this will make your vehicles safer' they will go out and do it.'
Last night, Richard's parents, Jim and Gwendolin Jones, who have three other children, described their son as 'just as mischievous as any lively six-year-old who like most children deserved and received a lot of love'.