The government has been asked to launch an urgent investigation following reports that Liz Truss’ phone was hacked.
The breach was revealed when Truss, then foreign secretary, was running for the Tory leadership in the summer, but the details were suppressed by then prime minister Boris Johnson and cabinet secretary Simon Case, the Mail on Sunday reported.
Spies suspected of working for Russian President Vladimir Putin gained access to sensitive information, including discussions about the war in Ukraine with foreign officials, the paper said, citing unnamed sources.
He also claimed that private conversations between Truss and Kwasi Kwarteng critical of Johnson fell into the hands of hackers, leaving them at risk of blackmail.
Opposition parties are calling for an inquiry into the alleged attack, which will raise questions about UK cyber security, as well as the trial of Johnson and Case.
Labour’s home secretary, Yvette Cooper, said: “There are extremely important national security issues raised by an attack like this from a hostile state, which will be taken extremely seriously by our intelligence and security agencies.
“There are also serious security questions about why and how this information was leaked or published now, which also need to be urgently investigated.
“It is essential that all of these security issues are investigated and addressed at the highest level and we need to know that the government recognizes the importance of this and the importance of fully protecting our national security.”
Liberal Democrat foreign affairs spokeswoman Layla Moran said: “We need an urgent independent inquiry to uncover the truth. Was Liz Truss’ phone hacked by Russia, was there a news blackout and if so why?
“If it turns out that this information was withheld from the public to protect Liz Truss’s leadership bid, that would be inexcusable.”
A government spokesman said: “We do not comment on individual security arrangements.
“The government has robust systems to protect against cyber threats. This includes regular security briefings for ministers and advice on protecting their personal data and mitigating cyber threats.