Two Bristol girls were turfed off a school bus because it was overcrowded – even though their parents had paid for their tickets.

Lauren Harrison, 12, and her friend, Rhiannon Beail, 11, were standing upstairs on the double decker when they were told by a bus driver to get off.

They were due to go home to Lawrence Weston after lessons at St Katherine's School in Pill.

Lauren, of Chapel Lane, said: "I felt really confused. I thought we were in trouble or something and the school wanted to talk to us.

"The bus driver was really rude.

"He was shouting at us, saying the bus wasn't moving until we got off."

The bus company says safety is paramount and they face heavy fines if they travel with too many pupils on board.

Lauren's parents, Simon and Becky Harrison, pay £3 a day in school bus fares for each of their three children.

Mr Harrison, 36, a pallet repairer and fork lift driver, said: "I think it's disgusting they were treated like this.

"They were not even given their tickets back.

"Lauren said she had paid the return fare but the bus driver just shrugged his shoulders."

Without their return tickets the two girls could not get on another bus.

When there is a problem pupils speak to the bus monitor – a teacher – but on this occasion the bus monitor was dealing with something else at that point and by the time the teacher was free all the buses had left.

Luckily, Mr Harrison was at home and came to collect the girls.

Mr Harrison said that when he complained to Eurotaxis Ltd, the firm which supplies bus travel at the school, he was told there was nothing they could do.

"These are young girls and you cannot expect them to walk so far home from school," said Mr Harrison.

"I'm a shift worker which meant that when they phoned home, I was available to go and get them."

He said some children were taken to school by their parents but caught the bus home which meant there were fewer seats in the afternoon.

Lauren said pupils often raced to get on a bus because there was never enough seats for them all.

She said four pupils often share two seats by sitting on top of each other.

Rhiannon's mum, Mrs Beail, 39, of Oakhanger Drive, said: "I'm pretty disgusted about it.

"I think the school should be trying to sort something out."

Tony Lavoie, business development manager of Eurotaxis, said there were more than 300 seats on the three double deckers the company uses for the school run and an average of 260 pupils use them each day.

He said: "We were very sorry to hear of the inconvenience caused to Lauren and Rhiannon. However, we take passenger safety very seriously.

"The law dictates that we may not overload any vehicle. The driver quite rightly asked the two passengers to leave the overloaded vehicle and to join another vehicle which was travelling the same route.

"Prior to the school buses leaving the school, the drivers ensured that all vehicles were not overloaded and that there were no children waiting to board buses.

"We cannot understand why these two children did not board one of the other buses. The three vehicles we operate have in excess of 300 seats with the average daily usage of 260 and therefore sufficient seats are available.

"When the vehicles leave the school, there is never overcrowding. However, once the vehicle is travelling, the driver has no control over children seat swapping."

The school's business manager Laurence Frewin said: "The school have been extremely concerned to learn of the problems experienced by students on their return journey home from school on Monday night.

"We have spoken to the operators of the public bus service, Eurotaxis, and have requested urgent action to ensure there is no recurrence of this situation, which is obviously unacceptable for any passengers let alone students."

It is not the first time parents have complained about the bus service to St Katherine's School.

In October last year three children from Lawrence Weston walked five miles to school because there was no room on the bus.

It took Becca Connor and Abigail and Tyler Johnston more than an hour before they were picked up by their head teacher Stephanie Quayle.

Hundreds of children from Bristol travel by bus to the North Somerset secondary school every day, paying £3 for a return ticket. Lawrence Weston and Shirehampton are some of the last stops on the route before the bus takes the motorway bridge over the river.

Eurotaxis was last year running five services to the school, but had to stop two of them because of restrictions placed on the operator by the traffic commissioner.

Traffic commissioner Sarah Bell refused the firm's appeal to be allowed to run more than 11 services at one time.