Thousands of drivers in England are being sent demands for up to £170 from private parking companies because of faulty ticket machines, campaigners have said.

Many private car parks require motorists to input their vehicle registration when purchasing a ticket from a machine, which is supposed to ensure they do not receive a parking fine.

Parking charge notices (PCNs) are issued when a ticket is not matched with a registration by automatic number recognition (ANPR) cameras that monitor entry and exit from car parks.

Parking companies send an average of 41,000 PCNs to drivers in Britain every day, according to government data analysed by the RAC Foundation and PA Media in November last year.

Many motorists, however, claim they entered their registration number correctly but still received a PCN.

Campaigner Lynda Eagan, who operates a Facebook group offering parking ticket help and advice that has 47,000 followers, said many machines were faulty but private parking companies continued to wrongfully pursue fines.

“We’ve got unfair PCNs issued to people simply because the machine didn’t work properly,” she said. “It’s a totally filthy business. It’s just wrong.”

Eagan believes thousands of drivers are wrongly being sent PCNs, the most common fault being “sticky keys” that do not correctly record number plates.

She also believes some machines – those that encourage drivers to pay before entering their registration, which is necessary to avoid a PCN – are “set up to trap people”.

The transport secretary, Heidi Alexander, described the issue as a “problem that needs to be tackled”, and the RAC has called for a government-backed code of conduct to be reintroduced.

A bill to introduce a code for private parking companies received royal assent in March 2019.

The code, which included halving the cap on fines for most parking offences to £50 and creating a fairer appeals system, was withdrawn three years later after a legal challenge from parking companies.

Interviews with drivers conducted by PA found that many continued to be pursued by private parking companies despite providing proof that they had paid for their ticket.

“Some parking companies are wrongly demanding ‘fines’ from drivers who have legitimately paid to park,” said Simon Williams, the RAC’s head of policy. “Whether it’s a faulty payment machine that records the wrong vehicle registration or an innocent mistake keying in their numberplate, these people shouldn’t have to pay the £100 parking charge notices they are sent. Many cases seem completely unjustified and should be thrown out at appeal. But sadly they so often aren’t.”

Alexander said she was working with colleagues in the Ministry for Housing, Communities and Local Government on implementing a code of practice. “We need to drive up standards in the private parking industry,” she said. “People’s experience is not good enough at the moment.”

Excel Parking, one of the UK’s biggest private parking operators, has also been criticised for charging drivers £100 if they take longer than five minutes to pay.

Earlier this month, a judge dismissed a claim by the company demanding £11,390 in charges from a driver and ordered it to pay thousands in legal costs.

Hannah Robinson, 21, received hundreds of letters and repeated phone calls demanding she pay the fines. She said she had paid for a ticket each time but sometimes it took longer than five minutes because of poor phone signal and problems with the payment app.

Excel Parking also dropped a £1,906 court claim in December against another driver who took more than five minutes to pay for their ticket.

Excel Parking did not respond to requests for comment about allegations of faulty machines.