Hundreds of motorists are being attacked every year by missile-throwing yobs. There were 395 incidents of rocks, stones or other objects being hurled at vehicles last year among the 10 police forces who responded to a Freedom of Information request by Autoglass.

This works out at an average of 39 per constabulary – or more than 1,670 incidents across the 43 force areas in England and Wales.

Many forces declined to give details of missile attacks on motorists on cost grounds but a quarter did. The reports from Lancashire (125 incidents), Northumbria (64), Nottinghamshire (64), Derbyshire (51), Essex (33), Suffolk (28), Avon and Somerset (12), Gloucestershire (12), Cambridgeshire (four) and City of London (two) gave some insight into the scale of the problem. Of those, the Suffolk constabulary said there had been 15 reported incidents of objects being thrown from bridges alone.

The problem was even worse in 2010 when the nine forces recorded 457 such attacks on motorists and moving vehicles.

Matthew Mycock, managing director of Autoglass, said: “It is horrendous that so many thugs are prepared to risk the lives of so many by targeting moving vehicles for fun.

“The alarming thing is that our findings are just the tip of the iceberg because they relate only the reported incidents and there must be many more cases where drivers don’t bother to alert the authorities.

“We know from the experience of our own technicians that missile attacks are a growing problem and a recent Autoglass survey found that a quarter of motorists have had their vehicles hit by a missile of some sort in the last five years.

“We would advise victims and witnesses to always accurately record these incidents and report them to the police to help eradicate such reckless behaviour and to save innocent UK road users from death or injury.”

Autoglass made the Freedom of Information request after two attacks on the A12 in December.

In one, Carol Manley, 57, suffered fractures to her face and ribs, and internal injuries after a lump of concrete was dropped on her vehicle from a bridge. Another motorist, Lisa Horne, 26, escaped unharmed when a rock the size of a football smashed through her windscreen.