BUS companies serving a Darlington estate say children as young as five are throwing stones at their vehicles.

The Green Bus Company and Stagecoach have reported children throwing stones at their vehicles on the Red Hall estate. Stagecoach says they also tamper with bus engine covers.

Richard Cranmer, of the Green Bus Company, said drivers were often having to contact the police because of children throwing stones at the buses.

"There are some very young children doing it, as young as five or six years old. The worst area is at the top of Coombe Drive and Bisley Court," he said.

"It is ongoing, but sadly worse this week. There has been no damage caused yet, but it is the public safety issue that most concerns us."

He warned that the company had withdrawn services in the past and would do so again if drivers felt it was becoming dangerous.

John Fraser, of Stagecoach, said the company's drivers had experienced similar problems.

"We are working very closely with the police and community wardens, who are passing on to the kids just how dangerous it is to lift the engine covers up or throw things at the vehicles. We are concerned for passenger safety," he said.

Police and community wardens on the estate are urging parents to speak to their children about the danger of throwing stones at vehicles and tampering with the buses.