Shops, restaurants and pubs among those hit by payment problem.
Many businesses have been forced to only accept cash as a card processing outage has left them unable to take debit and credit card payments.
The outage appears to have begun on Friday afternoon. I visited a pub and a shop in Central London at around 5pm on Friday evening, both of which were unable to accept card payments.
And the 'cash only' signs were still out today across the nation, with all of the retailers at Stafford service station on the M6 with the exception of M&S unable to accept cards.
The problem appears to lie with card processing company Global Payments, which is working to resolve the issue.
HSBC, which uses Global Payments' software to power its card processing machines, said on Twitter: "We are aware of an issue with merchant payments. Our third party provider @GlobalPaymentsUK are working hard to resolve".
If you're going out today, you might want to withdraw some cash to avoid being caught with no means to pay.
Have you had any problems? Let us know in the Comments below.