Sensitive trade documents leaked ahead of Britain's 2019 general election in an effort to interfere with the ballot were hacked from a former minister, it has emerged.
A report by Reuters said that hackers accessed the account of Liam Fox several times between mid-July and late October 2019.
Fox was international trade minister in former Prime Minister Theresa May's cabinet but lost his role on July 24 in a cabinet reshuffle after Boris Johnson won the Conservative Party leadership contest.
It is unclear which of his email accounts — whether the ministerial one or the parliamentary one — was hacked.
Among the information stolen were documents on the UK and US trade negotiations.
Foreign Secretary Dominic Raab accused "Russian actors" of meddling in the December 2019 general election last month by fraudulently acquiring and disseminating "sensitive" documents on social media.
Jeremy Corbyn, at the time the candidate for prime minister for the main opposition Labour party, said the leaked documents proved that the Conservative government planned to include the National Health Service in a future trade deal with the US.
A government spokesperson said in a statement that "there is an ongoing criminal investigation into how the documents were acquired, and it would be inappropriate to comment further at this point.
"But as you would expect, the Government has very robust systems in place to protect the IT systems of officials and staff," they added.
The investigation is being carried out by the National Cyber Crime Agency (NSCS).
The organisation stressed in a statement that it "works closely with political parties, local authorities and MPs, who are offered access to the best cyber security guidance and support."
"We have worked closely with political parties for several years on how to protect and defend against cyber attacks – including publishing advice on our website," it went on.
Liam Fox was nominated by the UK last month to become the next director-general of the World Trade Organisation.