POLICE are attempting to clamp down on motorists who warn other drivers of speed traps by closing an unexpected loophole in the law.

The Crown Prosecution Service is seeking a ruling that will make it easier to secure convictions against motorists who flash their headlights or wave warnings about speed cameras.

Ken Macdonald, QC, the Director of Public Prosecutions, wants the law lords to overturn a lower court ruling that makes it difficult to convict motorists who warn other drivers about radar traps. His move follows court hearings this year that cleared a motorist of obstructing a police officer in the execution of his duty.

Charles Glendinning, 56, was found guilty by magistrates but cleared on appeal when a court ruled that the police could not prove that any speeding motorist had slowed as a result of his actions.

The Crown Prosecution Service is seeking the right to go to the House of Lords to overturn the legal technicality on which he was cleared. It says that it should not have to establish that any driver slowed as a result of arm waving or the flashing of headlights before being able to win a conviction for obstructing a police officer.

The CPS has referred the case to the Appeal Court’s administrative court seeking leave to appeal to the House of Lords. The request said: “For there to be an obstruction of a PC in the execution of his duty by getting in the way of a police speed trap, is it necessary for the prosecution to prove that those warned were exceeding the speed or were likely to do so at that location?”

Mr Glendinning, of Yeovil in Somerset, was arrested last year and accused of obstructing a police officer in the execution of his duty. He denied that he was trying to warn other motorists of the speed camera on the A303 at Stoke Trister near Yeovil. Mr Glendinning said that his lorry had mechanical failures and he was warning other drivers that he was slowing to pull into a lay-by. He was pulled over by the police and found guilty by Yeovil magistrates last December of obstruction. In March he won his appeal against the conviction.

The CPS appealed, claiming that it should not have to prove that speeding drivers had slowed. The Court of Appeal dismissed the case.

Mr Glendinning said that he had spent £3,000 on the hearings at the magistrates’ and Crown courts. “I can only imagine how much this has cost the taxpayers already,” he said.

A spokeswoman for the CPS said: “Clearly there is an issue of law here that needs to be clarified and that is what we are seeking to do.”

FLASHPOINTS

• Motorists’ tactics to avoid detection include dirty numberplates and “anti-flash” numberplate spray — both are against the law
  
  
• In July this year the London Safety Camera Partnership returned £330,000 to motorists caught by speed cameras after there was found to be insufficient warning of a 20mph zone on the Embankment
  
  
• Anti-speed-camera demonstrators include a cyclist nicknamed Christ-on-a-Bike, who is accused of destroying 75 Gatso devices worth £1 million