Barclays said it is working to fix a problem that has caused duplicate payments across an undisclosed number of customer accounts.

A spokesperson for the British lender confirmed that the bank detected a "small number" of duplicate debit card payments this morning, but stressed that customer bank balances would be restored.

"We are working to fix this and refund customers as soon as possible. We apologise for any inconvenience caused and affected customers will not be out of pocket," Barclays' spokesperson said.

The bank has not provided any details on what caused the problem.

It is the latest payments debacle to affect British consumers this week - after a problem with Asda's card machines on Sunday caused long queues at checkouts across the country. The supermarket later apologised to customers and said it was working on fixing the issue.

Other UK banks have seen customer services impacted this year, including HSBC which was hit by a denial-of-service attack that temporarily shut down its online banking service in February.

In April, Barclays customers complained that they were unable to make payments from their accounts, an issue for which the bank later apologised and attributed to a routine systems update.

It marked Barclays' second payment systems glitch in six months, following a similar problem in October 2015.