Russian spies hacked Truss's personal phone
The breach was uncovered during the Conservative leadership contest this summer, but the news was suppressed.
Operatives suspected of working for Russian President Vladimir Putin hacked Liz Truss's personal phone when she was Foreign Secretary, according to a report by the Daily Mail.
The paper claims the hackers had access to 'top-secret details,' including conversations with foreign officials about the Ukraine war and information on arms shipments.
They were also able to read private texts between Truss and Kwasi Kwarteng, who later became Chancellor.
In total, the hackers allegedly downloaded up to a year's worth of messages.
The messages are said to have included criticism of then-Prime Minister Boris Johnson, which could have given the attackers leverage over Truss.
The hack was apparently uncovered during the Conservative leadership contest this summer, but the news was suppressed (perhaps to avoid biasing the contest. Conservative members knowing Russia had compromised their favourite candidate would be sure to affect voting - Ed.)
A government spokesperson refused to comment on individuals' security arrangements, but defended the Government's cyber defences.
"The Government has robust systems in place to protect against cyber threats. That includes regular security briefings for Ministers, and advice on protecting their personal data and mitigating cyber threats."
Ms Truss reportedly changed her mobile phone number for the first time in ten years just before entering Downing Street - where she worked for just six weeks.
Rishi Sunak took over as Prime Minister after Truss resigned on the 20th October.
Although it is unclear how the breach occurred, opposition parties have seized on the matter.
"There are immensely important national security issues raised by an attack like this by a hostile state which will have been taken extremely seriously by our intelligence and security agencies," said Shadow Home Secretary Yvette Cooper.
Cooper added there are serious security concerns about how the information was stolen and the news leaked, which the Government should urgently investigate.
Layla Moran, a member of Parliament and foreign affairs spokesperson for the Liberal Democrats, expressed worry at the delay in sharing details of the alleged hack.
"We need an urgent independent investigation to uncover the truth," Ms Moran said.
"If it turns out this information was withheld from the public to protect Liz Truss' leadership bid, that would be unforgivable."
Reports of the hack come as Rishi Sunak is resisting calls to investigate former (and as of last week, current again) Home Secretary Suella Braverman for her own security breach.
Sunak reappointed Braverman as Home Secretary just six days after she resigned for sharing a confidential document from her personal email account: a move that has already threatened to derail his promise to govern with "integrity and accountability."