Thousands of customers have been left without access to their internet banking as the Bank tries to resolve the matter.

A message posted by the bank on X, formerly known as Twitter, said: “We understand some customers are having trouble accessing banking services as usual right now.

“We’re investigating this as a matter of urgency and will share an update as soon as possible.”

The disruption has happened as the Black Friday shopping bonanza gets under way, with retailers slashing their prices.

One X user responded to HSBC UK’s message: “Literally the worst timing ever. People got paid and have bills to pay.”

Another said: “Got to move some money so I can buy some Black Friday purchases (that I don’t need) Maybe it’s a sign!”

HSBC UK said in a statement: “We’re working hard to restore HSBC UK’s mobile and online banking service, including the authorising of online card purchases via the app.

“We understand this is really frustrating for some of our customers, and we are really sorry for the inconvenience.”

Stephen Johnson, CEO at Roq said: “We don’t fully understand the technical issue at this stage – and we may never get to hear that – but the banking sector is notorious for a lack of investment in building resilience and quality into its systems.

“We have seen many big banks fail customers – TSB being very high profile – but financial repercussions seem not to be a true deterrent. Quality is just not at the forefront of decision making by high powered executives.

“As a customer, it’s not unreasonable that we expect our banks to provide a simple service. They make billions in profits each year and yet as a customer, we have reducing numbers of branches, we have unreliable technology and even uncertainty on whether the current economic climate will mean another banking crisis.”

HSBC UK said the issues its customers are having are not affecting customers of the brands First Direct or M&S Bank. The problems are understood to have been caused by an internal systems issue.