Officials have defended the use of a large bus, without seatbelts or supervision, to transport children as young as four home from school.

The headteacher of Buxton Primary School and a worried parent have complained at the introduction of the Sanders bus to ferry pupils to their homes at Badersfield, on the former RAF Coltishall site, which they think puts young passengers at risk.

Head Deborah Leahy said one or two parents had stopped their children using the bus. The school hadn't been consulted about the arrangement and she was not happy. The previous service had been a minibus, fitted with seat belts, but the Sanders buses were 'park-and-ride' size and were only used by 18 children. Ms Leahy said: 'The gaps between the seats are so wide, and the children - including four- and five-year-olds - are totally unprotected.'

The morning bus to school, which has seat belts, is provided by a different operator.

Mum Helen Kozakiewicz said she was so worried that she had stopped her five-year-old daughter Chenai using the Sanders bus and now collected her by car.

'She's only little and if the bus had to do an emergency stop she could be flung about like a pea. I don't feel it's safe for her to use it,' said Ms Kozakiewicz.

She claimed several other parents had similar misgivings but either did not have their own transport or were unable to collect their children in person at the end of the day.

A Norfolk County Council spokesman said the new service met all legal requirements and was run by a recognised operator with a strong safety record.

When the contract for the service came to an end in July they had put the work out to tender and Sanders had been successful.

'Their contract offered the best value for money for taxpayers and operated as a local bus service, meaning we could make use of a bus already operating in the area and remove an additional vehicle from the road,' she said.

'Sanders will make the decision on what vehicle to provide on the service but their buses will all comply with the law.' The previous minibus service, like the Sanders bus, had not included an escort.

Charles Sanders, managing director of Sanders Coaches, said they needed to use a 43-seater bus because once it had dropped off the Buxton School children it travelled on to Aylsham High School to collect far more pupils there.

He pointed out that under the law the bus could legally carry 20 passengers standing up as well which he said 'made a mockery of seatbelt laws.'

Mr Sanders added that buses were statistically safer than either cars or trains.