Marks & Spencer was forced to suspend its website after an apparent security breach.
The breach resulted in customers being able to see other people’s details when they logged into their accounts.
M&S said that customers may have been able to see the last four digits of another person’s payment card, "for a brief moment."
The retailer blamed the problem on a "technical issue" which resulted in it suspending its site.
A spokesperson said: "This allowed us to thoroughly investigate and resolve the issue and quickly restore service for our customers. We apologise to customers for any inconvenience caused."
The website was taken down at around 6:30pm on Tuesday night and restored by 9pm.
Keith Poyser, MD, EMEA, Accellion, said: From Sony to TalkTalk, this issue continues to rear its ugly head, yet cyber security is still not ingrained at every level of UK organisations’ cultural mindset.
"That means cyber security must reach everything and everyone, from the latest tech to even the savviest employee."
