The person who dropped an object from a bridge onto a vehicle travelling along the A47 near Norwich has been condemned for their actions which police say could have killed someone.

Police are investigating an incident of criminal damage which happened on the A47 eastbound carriageway at Intwood, near Cringleford, Norwich.

A blue Land Rover Freelander was struck by an unknown object. The driver heard a bang and the noise of breaking glass from their sun roof. No-one was hurt but the female driver and her passenger were shaken.

Police said the motorist was lucky not to have been killed following the incident which happened on Friday, December 17 and have urged witnesses to come forward.

PC Glen Boreham said: 'I'd appeal to anyone who witnessed the incident or has knowledge of it to come forward and tell police. This act was extremely irresponsible and dangerous and could have caused a serious injury or even a fatality. The motorist involved was very fortunate not to be seriously hurt.'

The incident at Intwood follows two incidents earlier this month where 'bucket-sized' concrete blocks were dropped on to passing cars on the A12 in Essex, which are being treated as attempted murder.

Carol Manley, 57, suffered life-threatening injuries when a block smashed the windscreen of a car passing under West Hanningfield bridge, on Thursday, December 1.

Half an hour earlier, mother and daughter Lisa and Stella Horne were left shaken after a block went through a windscreen at Fryerning Lane bridge.

Police are linking the attacks, which happened about eight miles apart.

Mrs Manley, from Harold Hill in Essex, suffered multiple rib and facial injuries when a bucket sized block smashed through the windscreen of the Nissan car being driven by her 56-year-old husband, who suffered cuts.

The couple were returning home after visiting friends when their car was hit by the concrete block just after 10pm.

Lisa and Stella Horne were returning from a shopping trip in the Chelmsford area, were both unhurt but badly shaken.

Speaking about these cases, Ch Insp Nick Morris of Essex police said: 'It is attempted murder. If you throw a large piece of concrete off a road bridge on to a large, busy road, you are likely to kill someone. It's only by pure luck a lady was not killed.'

Anyone with information about the Intwood incident should call PC Glen Boreham on 101.

Have you got a crime story? Call Peter Walsh on 01603 772436.