"When you stand back and think about it, it's a proper rip-off," said Flexed.co.uk spokesman Mark Hall. "It's maddening when they charge an odd figure like 60p for an hour's parking, knowing full well that most drivers will probably only have a pound coin."

"Those extra 40p charges soon add up."

According to a report last year, local authorities raise up to £10m annually by not giving change from parking machines. According to the Daily Mirror, Wiltshire Council came out top, overcharging to the tune of £723,000 in 2013.

Drivers finding themselves – literally – short-changed were outraged by councils who refuse to give more sensible options for parking.

The emergence of parking apps for smartphones may eventually end this problem for council areas that refuse to update their parking machine cash cows, but this comes with its own set of problems, Flexed.co.uk says.

"Number one of these is people who have yet to make the jump to new technology," said Hall, "Elderly motorists in particular don't have the confidence to use remote payments, leaving them stuck with greedy parking machines robbing them blind."

The second problem with parking apps is the number of services available.

One driver told Flexed: "Parking apps ought to be really convenient, but they are a horror to use. Half the time they forget your card number, or you're driving a different car, so you have to stand by the machine entering your details all over again… And there are four different apps covering parking in my home town. I've actually got a folder on my phone specifically for them."

"Many people think there's a war on motorists conducted by governments and local councils," concluded Hall. "And the fact that so many authorities are ripping off drivers like this makes them believe it to be true."

"Motorists deserve a fair deal, even on 40p's worth of parking."