HSBC’s online banking website is down, leaving thousands of customers unable to access its services after a cyber attack.

Anyone attempting to access their account was receiving an error message on Friday morning reading: “We’d like to apologise to all our customers for Online Banking being unavailable.

“We know how inconvenient this is and we are doing everything we can to rectify the problem. Please try later.”

The error message showing on the website on Friday morning. (HSBC)

A spokesperson said HSBC had been hit by a distributed denial of service (DDos) attack but did not say if the source was known.

“HSBC internet banking came under a denial of service attack this morning, which affected personal banking websites in the UK,"she added.

"HSBC has successfully defended against the attack, and customer transactions were not affected.

"We are working hard to restore services, and normal service is now being resumed."

The company was directing people still experiencing problems to use its automated telephone banking services instead.

A DDos attack, which floods websites with traffic from multiple systems, was also the method used to down BBC websites on New Year's Eve.

An anti-Isis hacking group called New World Hacking claimed responsibility, saying it was "only a test" of server power.