High street giant WHSmith says it has suffered a cyber attack in which hackers accessed employee data.
Hackers are understood to have accessed information pertaining to both current and former members of staff as part of the breach on Thursday.
WHSmith said the incident has not impacted its trading activities and stressed its website, customer accounts and customer databases are on separate, unaffected systems.
A company spokesperson said: “Upon becoming aware of the incident, we immediately launched an investigation, engaged specialist support services and implemented our incident response plans, which included notifying the relevant authorities.”
It added: “WHSmith takes the issue of cyber security extremely seriously and investigations into the incident are ongoing.
“We are notifying all affected colleagues and have put measures in place to support them.”
The breach comes amid a wave of cyber attacks in recent months, with Royal Mail’s international postal service suffering lengthy disruption after hackers targeted the group.
Retailer JD Sports also warned in January that around 10 million people might have had their addresses, phone numbers and email addresses stolen – among other things – in a hack.