One of the UK's largest private parking providers is being investigated by the competition regulator over whether parking tickets for drivers queuing at petrol forecourts are fair.

Euro Car Parks' broader appeals process relating to petrol stations and car parks is also being looked into, to determine if it breaches consumer protection law.

The investigation forms part of a wider crackdown by the Competition and Markets Authority (CMA) into potentially unfair practices by private parking operators.

Research by the RAC has suggested the number of tickets issued in places like gyms, supermarkets, restaurants and retail parks more than doubled in six years, to 14.4 million.

Motorists have complained about these parking issues, the CMA said, highlighting problems including unclear signage, faulty apps and broken ticket machines.

The regulator said it wanted to make sure drivers are being treated fairly following complaints from motorists who feel they've been unjustly issued with parking tickets.

The CMA says it has its own concerns about the way some operators are handling appeals, or attempting to make motorists pay additional fees on top of parking charges.

It has written to the sector as a whole, and issued warnings to some individual operators about their practices.

The CMA's executive director of consumer protection Emma Cochrane said receiving a parking ticket could be a stressful experience.

"Costs are high and often unexpected which is difficult when people are budgeting carefully," she said.

"Parking companies must treat motorists fairly at all stages – and a clear and consistent appeals process must be at the heart of this.

"It's time for all private parking operators to comply with consumer law or risk action from the CMA."

In the open letter to private parking operators, the CMA warned they should review their terms and conditions and make changes if necessary to ensure they are complying with consumer law.

The CMA's investigation into Euro Car Parks is focusing on whether it is fair for drivers to receive parking charges while queuing for, or using, petrol pumps and other forecourt services such as car washes, plus its wider appeals process.

It is in the evidence gathering stage, and is set to run until Spring 2027.

Euro Car Parks has more than 3,000 facilities across the UK and Ireland, according to the company's website, with more than two million cars parking in their spots every day.

The BBC has contacted Euro Car Parks for comment.

RAC head of policy Simon Williams said the CMA's effort was a "major step forward in ensuring drivers are treated fairly by private parking operators".

He pointed out the watchdog's crackdown comes ahead of the government's response to a consultation on reinstating the withdrawn Private Parking Code of Practice.

"The CMA has shone a much-needed light on the appeals process and found major problems that need to be addressed," he said.

"We strongly hope the code will give us a single independent appeals body, instead of the two we have now – one for each of the two trade associations."

One of the parking trade bodies, the International Parking Community, said it welcomed the CMA's efforts to ensure motorists are treated fairly.

"We received the CMA's letter on 16 July and are reviewing it carefully," a spokesperson said.

"We have already shared the CMA's open letter with our members and will issue detailed guidance to help them ensure their practices fully meet the standards it sets out."

The British Parking Association (BPA) is also reviewing the CMA's letter and said it will implement recommendations where appropriate, adding that it has "always strived to strictly uphold the highest industry standards" among members.

"While continuing to support our members, our focus remains on driving improvements across the UK parking industry and engaging constructively with all parties, providing a fair, transparent and effective parking framework for all motorists," BPA's head of external affairs Isaac Occhipinti said.

Tips to avoid parking problems

• Check the rules for each car park you use, which should be set out in signs in the car park, as not all car parks work in the same way
• Free parking periods may not be automatic - check to see whether you need to register your car's details or scan a receipt
• Payment machine isn't working, or your car breaks down? Make sure to keep evidence, including photos and receipts
• If you believe you've received a ticket incorrectly, appeal it within 14 days
• Know that you always have the right to appeal a parking charge notice