The UK is increasingly becoming a cashless society as more people rely on cards and apps to make payments.

However, a survey of more than 2,000 people by the consumer group found one in seven were left unable to use their card due to an outage last year and half said they couldn’t pay for goods and service as a result.

Worryingly, one in 20 experienced a problem more than once.

Even more alarmingly, one in 10 suffered a financial penalty as a result of not being able to use their card, and the same proportion said their credit score was damaged because they missed a bill or payment.

Which? said the findings demonstrate the vulnerability of digital banking and payments.

One in five of those left unable to use their card due to an outage now keep more cash with them, according to the research.

Customers locked out every day

Separate analysis from Which? that looked at FCA records of bank IT outages revealed that over the last year customers suffered a system failure that led to them either being locked out of their account or unable to make a payment almost every day.

Overall, there were 362 incidents reported by UK banks in the 12 months to 31 March this year.

Almost two million people currently rely on cash for their daily transactions – but despite the combination of a widespread appetite for cash and the high rate of digital payment failures, access to cash is declining rapidly.

The UK has lost two thirds of its bank branches in the last 30 years and over 60 branches continue to close every month.

Meanwhile, cashpoint closures have surged, with almost 220 free-to-use machines closing monthly in 2018.

Gareth Shaw, head of money at Which?, said: “Digital payments have enhanced many people’s lives – but many still rely on cash and all of us risk being shut out of paying for goods and services when technology lets us down.”