POLICE are appealing for witnesses after a concrete block was thrown at a moving bus in Darlington.

The Stagecoach bus was travelling under the North Road railway bridge at 4.20pm on Tuesday, when the block was thrown at the front window.

The window cracked, but the driver of the bus, which had several passengers on board, managed to bring it to a halt.

Police believe the concrete block was thrown by someone standing on the railway bridge.

Detective Constable Alex Francis, of Darlington Police, described the attack as very dangerous.

"It could have been very serious indeed, and we would appeal for witnesses or anyone with information about the incident to contact us," he said.

Paul De Sanctis, operations director for Stagecoach, said: "It was lucky the vehicle did not go out of control, because we could have had a major incident on our hands."

Anyone with information can contact Darlington Police on (01325) 467681