Mr Burke with the three signs at the centre of the case

Acting Assistant Chief Constable of Cleveland Police John Burke was speaking after a row involving "non-prescribed" or incorrect speed camera signs in his force area.

Two officers from North Yorkshire Police successfully challenged speeding charges at Guisborough Magistrates' Court after being allegedly caught on camera exceeding the 50mph limit on the A171 in summer 2002.

It was alleged North Yorkshire Police constables David Burlingham, 47, and Andrew Macfarlane, 35, broke the 50mph speed limit on the road in two separate incidents last summer.

The officers claimed the thin black border around the joint 50mph speed limit and speed camera warning sign had not been prescribed by the Department of Transport.

At Guisborough Magistrates Court last week, the officers were told the Crown Prosecution Service was not offering evidence against them.

Signs replaced

Mr Burke told a news conference: "Of course it's embarrassing, it smacks of double standards.

"I'm extremely disappointed, what we have got here is a legal technicality. But this will not deviate us from our course - to reduce casualties."

Mr Burke said the Chief Constable of North Yorkshire Police, Della Canning, had not yet responded to a letter he had sent but she told him she was unhappy about the case.

He said Burke said all the incorrect signs in his area had been now been replaced.

The signs, erected by Redcar and Cleveland Borough Council, were deemed not to be legal because they had a black border on them.

Nine collisions

Now the authority says it has erected replacement 50mph signs in the stretch of road and elsewhere throughout the borough.

Mick Bennett, spokesman for the Cleveland Safety Camera Partnership, said there had been just nine collisions on that section of the A171, compared with 70 in the previous three-and-a-half years.

And he urged people to reconsider before challenging a speeding ticket.

A North Yorkshire Police spokesman said the force was considering the implications of the case.