The likelihood of getting off a parking fine depends on which area of the country drivers get a ticket, with some councils approving as few as one in 10 challenges while others accept nearly every appeal.
On average just over a third (38%) of initial driver challenges to on-street parking fines made to local authorities in England between January and October 2016 were successful, according to figures obtained by the Press Association through Freedom of Information requests.
But there was huge variation between councils, with Runnymede, Surrey, accepting just 9% of appeals while Basingstoke and Deane, Hampshire - just 30 miles away - approved 95%.
Guy Anker, managing editor at MoneySavingExpert.com, said: "If the councils accepting the fewest challenges are wrongly rejecting claims it's an absolute disgrace."
The figures show that Runnymede, famous for being where King John sealed Magna Carta, received 1,011 challenges to parking fines in the requested period, with only 93 being accepted.
Staffordshire County Council also accepted challenges at a rate of around one in 10 (10.4%).
By contrast, Basingstoke and Deane accepted 540 challenges out of 566 - a rate of more than 95%.
Next highest were Waveney (Suffolk), South Tyneside and Swale (Kent) councils, who all accepted around seven in 10 appeals.
Regional variation was particularly noticeable in Berkshire - drivers in Slough (23%) were nearly three times less likely to get off their ticket than in Bracknell Forest (64%), a mere half an hour's drive away.
Meanwhile in Medway, Kent, drivers were half as likely to have their fine cancelled, at a rate of 32%, than in neighbouring Swale, where 71% were accepted.
Mr Anker said: "We hear so many stories from motorists who are victims of overzealous parking wardens.
"Often the real problem is really poor, terrible signing. People are often completely bamboozled, can I park here or can I not?"
Mr Anker said that after having a challenge rejected by the council, around 50% of drivers who make a further appeal to the independent Traffic Penalty Tribunal are successful.
He said: "I would encourage everyone who feels they are being harshly treated by their council to make an appeal to the independent arbitrator."
A spokeswoman for Runnymede Council said: "The statistics provided relate to street matters only which often refer to yellow lines and dropped kerbs.
"This therefore means there aren't very often cases which are open to much ambiguity. We use our own staff to carry out enforcement, who are experienced and well trained in the role and therefore only issue notices where necessary."
Basingstoke and Deane councillor Simon Bound said: "We take a pragmatic approach to enforcement which means that we see a very low number of formal appeals and we will consider each case carefully, taking into account individual circumstances.
"Parking enforcement is a means of educating, not punishing motorists. Our priority is ensuring that motorists park correctly and safely and that they continue to do so in the future."
The PA asked councils for the number of initial challenges to on-street parking fines they received from drivers between January and October 2016, and how many of those the council had deemed successful.
To ensure a fair comparison, the survey only covered the first challenge made by the driver, and not any further action that was taken.
The 98 councils who responded to the request with sufficient data referred to this in different ways, for example as an "informal challenge" or "initial appeal".
The five councils which accepted the fewest challenges were:
:: Runnymede - 93 challenges out of 1,011 (9.2%)
:: Staffordshire - 478 challenges out of 4,606 (10.4%)
:: Sefton - 650 challenges out of 4,832 (13.5%)
:: Peterborough - 410 challenges out of 2,784 (14.7%)
:: Greenwich - 1,018 challenges out of 5,909 (17.2%)
The five councils which accepted the most challenges were:
:: Basingstoke and Deane - 540 challenges out of 566 (95.4%)
:: Waveney - 164 challenges out of 226 (72.6%)
:: South Tyneside - 1,474 challenges out of 2,074 (71.1%)
:: Swale - 3,342 challenges out of 4,721 (70.8%)
:: Mole Valley - 144 out of 224 challenges (64.3%)