Thousands of past and present members of the armed forces have had their payroll details hacked in an attack on Ministry of Defence data.
Defence secretary Grant Shapps is due to update MPs on the incident, which is understood to have taken place earlier this month, later today.
The data breach reportedly involves a payoll system for current service personnel, as well as some veterans. CSW understands that civilian staff are not affected.
MP Tobias Ellwood, chair of parliament's Defence Select Committee and a former captain in the Royal Green Jackets, told Sky News he believed China was responsible for the attack and that it was "probably looking at the financially vulnerable with a view that they may be coerced in exchange for cash".
In March, deputy prime minister Oliver Dowden told parliament that China had been responsible for "two malicious cyber-campaigns" targeting UK democratic institutions and parliamentarians. One involved the Electoral Commission; the other involved "reconnaissance activity" against UK parliamentary accounts in 2021.
In September, a government report to members of parliament's Intelligence and Security Committee said China posed a "systemic challenge" to UK security, with civil servants and former officials among the targets.
The report said MI5 was running seven times as many investigations into Chinese activity compared with 2018 “and plans to grow further”.
An MoD spokesperson confirmed Shapps's plans to deliver an update to MPs.
“The defence secretary will make a planned statement to the House of Commons this afternoon setting out the multi-point plan to support and protect personnel,” they said.