Police have issued a stark warning after a rock thrown by school kids from a motorway bridge smashed a HGV’s windscreen.

It happened on the M602 westbound in Weaste, Salford, at around 4.20pm this afternoon.

Witnesses say that a group of children wearing school uniforms had been stood on top of the Weaste Lane bridge throwing stones and rocks at cars below.

One hit the windscreen of a HGV smashing it.

PC Matt Picton from GMP Traffic said it’s lucky the rock wasn’t any bigger as it could have shattered the windscreen completely.

He said “It’s not worth thinking about what would’ve happened if the windscreen had shattered when the driver was travelling at speed along the motorway.

“It just takes a heavy goods vehicle like this to jack-knife and there could be a fatal RTC.”

The children thought responsible for the damage ran off before officers could find them but PC Picton said they will be visiting local schools to speak to pupils about the dangers.

He added: “People need to realise the potential consequences of doing something stupid like this.

“It’s not acceptable and anyone caught will be dealt with by means of prosecution.”