Private company TPS Parking Solutions Ltd monitors the car park through CCTV. It uses information obtained from the DVLA to send letters demanding money for parking fines.

The system has provoked criticism from pressure group The Association of British Drivers and several MPs, who are against drivers’ details being sold to private companies.

SNP Councillor Craig Melville — who was recently elected to the Maryfield ward — said he believes the fines may not be legally enforceable, and urged motorists to seek advice before paying them.

“According to my advice, these fines are probably not valid unless a case is brought against you in a civil court,” he told the Tele. “The ‘charge’ is alleged under contract law.

“This will not stop them threatening you with enforcement action but, according to my advice, they can only enforce it by bringing litigation against you in a civil court.”

Mr Melville said a campaign by shoppers in Arbroath last year led to Lidl dropping the charges at its store in the town.

“The company decided to abandon its agreement with TPS Parking Solutions, removing CCTV and reverting to employing their own attendant,” he said.

“Obviously, I would hope that shoppers at Lidl would adhere to the terms of the free parking and not overstay, but if they do, they should seek legal advice on the validity of any letter demanding money for parking fines.”

The issue came to light when one disgruntled shopper contacted the Tele after she received a fine and paid up, believing the letter was a legal document.

“I had parked there to do some shopping, and I must have overstayed by 20 minutes or so,” she said.

“I was astonished to get a ticket in the post a week later, saying that I had to pay a fine of £45 or else it would go up to £70.

“Because my details had been given to the firm by the DVLA and the letter looked official, I assumed it was a legal notice.

“I thought I had no option but to pay it, so I sent off a cheque.

“It wasn’t until I looked it up on the Internet a few days later I realised these fines are issued on a shaky legal basis, and I probably shouldn’t have paid it.

“I’m angry at the way Lidl operates the car park. The fact you don’t need a ticket seems to be a way of catching people out, so they can generate more money from the fines.

“They’re fleecing their customers. I won’t be parking — or shopping — there again.”

A spokesman for Lidl told the Tele the scheme was not designed to penalise customers, but to deter other motorists from abusing the facilities.

“At Lidl, we take the opinion of our customers very seriously,” he said.

“Car park management has been introduced in several stores across the nation. This was prompted by many of our customers bringing the issue of parking to our attention.

“It transpired we had car parks which were being abused by non-Lidl customers, and this was the way to prevent car park misuse.

“We have had many letters of support as our customers can now park with ease at our stores.”

The spokesman added that Lidl shoppers who overstayed in the car park could contact its customer hotline on 0870 444 1234.

“We are confident genuine Lidl customers will not be penalised by this system,” he said.