A speed camera case has been dropped at a Teesside court after police were unable to show they had followed strict guidelines.
Months of painstaking detective work by Redcar garage owner Lawrence Lewis saw Cleveland Police throw in the towel over his daughter Julie's disputed ticket more than two years ago.
But their lawyer has warned the case is unlikely to open the floodgates to similar climb-downs.
Mr Lewis took up the fight after his daughter was snapped by a mobile unit after turning into Eston High Street from Birchington Avenue in September, 2001.
The subsequent ticket claimed she was doing 36mph - but both Julie, who had only recently been fined £60 for another speeding offence, and her young son were adamant her speed was well below 30mph.
Mr Lawrence decided to challenge the ticket and research then led him to guidelines issued by the Association of Chief Police Officers on the use of mobile speed cameras and the testing and calibration required to render readings legal.
When the case finally reached Teesside Magistrates' Court, the Crown Prosecution Service dropped the action after the Lawrences' solicitor asked to see the relevant calibration material.
The guidelines require a test run to check the camera's accuracy before and after members of the public are snapped, but the records were available to show only the first was carried out.
Mr Lewis said: "They initially denied the second run-through was required under the old guidelines, and applies only under the new ones.
"But I was able to produce a copy of the old guidelines from my briefcase and they do say there should be a second calibration check at the end of the deployment."
Solicitor Graham Brown, of Redcar-based law firm Brown, Beer and Co, said: "Each case has to be looked at individually.
"If you really dig into one of these cases with a client who maintains they were not speeding, various things come out of the woodwork.
"The prosecution has to show they were complying with the guidelines and assert that they could establish the reliability of the equipment and they were unable to do so.
"However, the vast majority of people won't have the time, resources and energy to challenge their cases in this way.
"It might have great relevance for someone who has been convicted and disqualified and suffered in their career as a result. But they would first have to apply for leave to appeal against their conviction out of time to the Crown Court and indicate they were not embarking on a fishing expedition."
Cleveland Safety Camera Partnership spokesman Mick Bennett said computer records were produced from camera deployments, including print-outs of the drive-throughs, before and after the session.
He said: "In this particular case the offence was more than a year old before it got to court because of adjournments the defence had asked for. We had lost the last piece of paper and we couldn't prove to the judge that we had carried out the checks in accordance with the handbook.
"Nobody suggested these checks weren't done and that wasn't the issue. We have now put a system in place that will prevent this ever happening again."
