WH Smith has said it has been the target of a cyber attack, with hackers gaining access to company data.
The high street retailer added that the hackers were also able to access current and former employee information.
The company said the hack had not affected its trading activities, stressing that its website, customer accounts and customer database were on separate systems that were not affected.
“When we became aware of the incident, we immediately launched an investigation, engaged specialist support services and implemented our incident response plan, which included notifying the appropriate authorities,” WH Smith said.
It added: “WH Smith takes cybersecurity issues very seriously and is investigating the incident.
“We are notifying all affected colleagues and steps have been taken to support them.”