HSBC has experienced a major IT outage that has caused its online banking and some ATM services to go down.
Customers have also reported their bank cards being rejected when trying to pay for goods in supermarkets.
The bank said that the fault began at 14.45 GMT, according to BBC News.
HSBC’s UK press office Twitter feed posted messages saying that it was aware of the problems.
“We are aware of some problems and are looking into them as a matter of priority.
“Sorry for the inconvenience, especially on a Friday,” the messages said.
The bank's communications team appears to be trying to keep customers regularly updated. A few minutes ago, the press office added: “Sorry – we are having issues with our systems. Working to fix it ASAP. When we have an update, will tweet it from here #HSBC.”
However, calls to the press office were met with voicemails.
A number of banks have experienced problems with their online services, with the most recent case being the Bank of Scotland and Halifax, a problem that customers are still experiencing nearly two months after a systems migration carried out by parent company Lloyds Banking Group.