Two officers from North Yorkshire Police were charged with speeding as they drove along the A171 near Guisborough in 2002.

But Cleveland Police were forced to drop the case, when the pair were advised by a colleague that road signs warning drivers about speed cameras were incorrect.

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

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

The council says it has removed the combined signs, with a black border, of the 50mph speed limit and the speed camera logo, and is replacing them with two separate signs on the same pole.

Legal loophole

The council's cabinet chairman, Eric Empson, said: "We are now satisfied that all the signs are enforceable."

The Chief Constable of Cleveland Police hit out at the serving officers from the neighbouring North Yorkshire force, who used a legal loophole to avoid speeding charges.

Sean Price said: "Any reasonable person on seeing the sign would know it meant it was not safe to exceed 50mph.

"I do think it is particularly unfortunate that the defendants were serving police officers.

"I think it is a legally absurd principal that speeding fines are to be escaped because of a legal technicality."

The signs were erected as part of the Cleveland force's pilot scheme to crack down on speeding. They had a black border which infringed the Road Traffic Regulation Act.

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.

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

Redcar and Cleveland council chief executive David Moore has written to Della Canning, the chief constable of North Yorkshire Police, demanding the officers be disciplined for allegedly breaking the speed limit.