A motorist has expressed his frustration after a police investigation into a rock thrown at his car was dropped 45 minutes after he filed a detailed report.

Mike Gibbins, 60, was left shaken after his BMW was struck by the large stone thrown by a youth as he drove through the centre of Wymondham.

After calling the police 101 service to report it he was told officers were busy and he would be called back four days later.

But after giving a detailed account during the arranged call-back he was dismayed to receive an email 45 minutes later stating "there were no lines of enquiry which would be proportionate for us to pursue this so this investigation will be closed".

“I realise this is not the Great Train Robbery in the grand scheme of things, but ultimately this stone could easily have gone through the windscreen or bounced off and struck a pedestrian,” he said.

The youth who threw the rock had been part of a group of school students in uniform standing on a grass bank near traffic lights on Station Road.

Mr Gibbins, a retired chartered accountant who lives in Wymondham, said he had been told police would be contacting the school as part of their investigation while community officers would also be looking into it.

But after making his own enquiries he believes this did not take place.

“It’s really annoying that they said they were going to do something and they didn’t,” he said.

“Thankfully the damage to the front grille of the car was fairly light but this young person seems to have no concept of their actions and the potential consequences. What is to stop him doing this again in the future?”

A Norfolk Police spokesperson said they had been provided with a “limited description” and that Mr Gibbins had said he would not be able to recognise or identify the suspect again.

“After reviewing all the evidence, no realistic lines of enquiry were identified and the crime report has been closed pending any further new evidence coming to light,” they added.

“The local beat manager has been made aware of the incident should any similar incidents be reported.”