Mum-of-three June Proctor, of Corner Farm in Long Drax, said the school service, which replaced the Stockdale Bus service in Easter 2009, had caused concern since it was implemented.

She said she spoke for many mums, who were equally worried for their children travelling to and from The Snaith School and Carlton Holy Family High School.

June added: "Sometimes, 70 to 80 children are packed into a single decker bus.

"Being packed in like sardines I feel is very dangerous. An accident could easily happen. I fear for my special needs son Andrew, 14, who has a heart problem and my 16-year-old daughter Bethany, who have to travel from Long Drax to Drax to catch the bus and are regularly kept waiting about 50 minutes.

"This not only makes them late, but puts their health at risk as they're out in the cold. The bus is packed, the students are crushed together and have to stand in the aisle. This isn't good.

"My friend Wendy Bond has contacted Arriva and North Yorkshire County Council Integrated Passenger Service Department about this without satisfaction. Something needs to be done!"

Arriva Yorkshire managing director Nigel Featham said: "At Arriva Yorkshire, we strive to provide the best possible service for all our customers.

"We've discussed the pros and cons of making changes to this service with North Yorkshire County Council and, I'm pleased to confirm that, from April 12, we will allow more time for the journey in order to improve its punctuality.

"Also, we're looking into parents' comments about the amount of children wishing to use the service and, if need be, we will allocate a larger vehicle to cater for demand."