Police have launched a public attack on a retired bank manager who criticised their speeding policy after he was convicted of breaking the 30mph limit.
William Shaw said he broke the speed limit to overtake a tractor
In a highly unusual move, North Wales Chief Constable Richard Brunstrom called a news conference to hit back at 71-year-old Bill Shaw.
Mr Shaw had said his prosecution for doing 39mph in a 30mph zone was unfair, and ended his 50-year clean driving record.
But police produced video footage which they said showed Mr Shaw had not been speeding to overtake a tractor, as he had claimed.
Mr Shaw, of Llangollen, had pleaded guilty three weeks ago to speeding in Flintshire in the hope that magistrates would reject the case.
He claimed he had completed a safe manoeuvre and police were hitting "soft targets" like him.
Magistrates fined him £60, with £30 costs and three penalty points, and said they had "every sympathy" with him.
Richard Brunstrom shows the video footage to journalists
But magistrates' chairman Kathleen Cottle said their hands were tied and had to follow guidelines.
Mr Brunstrom has now accused Mr Shaw of giving a misleading account.
Video of the moment when he was caught in his BMW was shown at the news conference, and reporters were handed 31 photographs of the sequence.
Mr Brunstrom told BBC Radio Wales that Mr Shaw had touched a nerve.
"I'm extremely disappointed by the irresponsible attitude of somebody in Mr Shaw's position," he said.
He said speeding was anti-social, dangerous and affected lives, and the spot where Mr Shaw was caught was where a young pedestrian had been killed.
"There are many people who believe that we are persecuting motorists," he told the Good Morning Wales programme.
"There are many people who have been caught who think we are acting unfairly and that's really why I'm so concerned about what Mr Shaw said because he is misleading the public.
"What he said is simply not accurate and I must ensure that the public have the true facts so that if they wish to continue to support our campaign they can do so."
Mr Brunstrom accepted that police had to strike a balance between the need to save lives on the roads and to tackle anti-social behaviour on the streets.
Police say video demonstrated that Mr Shaw was not overtaking
But he had no regrets about the attack.
"I don't particularly want to personalise this," he said.
"It's a step I didn't take lightly, I've never done it before and I would seek to avoid doing it as general practice.
But he said Mr Shaw's allegations were "grossly inappropriate and totally incorrect".
Mr Brunstrom said anti-speeding was "most certainly" a personal crusade for him. There were 13 people alive in north Wales alone who would otherwise have died last year.
"The danger of course of being engaged on a crusade is that you lose context and you become fixated on one objective and of course I must make sure that doesn't happen to me."
When Mr Shaw was told later about the criticism, he said the chief constable must be desperate to make such a fuss over such a trivial case.
He said Mr Brunstrom had placed his own interpretation on events.
Mr Shaw was upset that the chief constable suggested he was driving dangerously, when he said he obviously was not.