Prime Minister Andy Burnham exchanged messages with a person posing as the chief of staff to US President Donald Trump.
Downing Street has declined to comment on the security breach, first reported by Politico.
Politico reported that officials said Burnham communicated with the person claiming to be Susie Wiles “before becoming suspicious that the contact was illegitimate” and claimed only a “few messages” were exchanged.
A government spokesperson said: “We do not comment on national security matters.”
It is understood the communication between Burnham and the person posing as Wiles was in the form of messages and there was no conversation between the two.
“No messages of significance” were exchanged and the texts were “quickly reported to the appropriate authorities” once they were believed to be suspicious, sources said.
The BBC has previously reported an FBI probe into Wiles’ phone being hacked in May last year.
At that time, Wiles said her phone had been hacked after an impersonator, or impersonators, used her contacts file to message other top US officials.
The impersonation was targeted at her personal phone, not government phone, but recipients included US senators, governors and top business executives.
Wiles, a key Trump ally, was also among those targeted by a cyber espionage unit associated with Iran’s Revolutionary Guards – a powerful branch of Iran’s armed forces – in 2024.
The White House has been contacted for comment.
In 2024, the Foreign Office (FCDO) confirmed then-foreign secretary David Cameron had fallen victim to a hoax call with someone pretending to be former Ukrainian President Petro Poroshenko.
Lord Cameron also exchanged some text messages with the impersonator pretending to be Poroshenko, who was president of Ukraine between 2014 and 2019.
During his term as prime minister, Lord Cameron had multiple dealings with the Ukrainian leader, including meetings at international summits.
The FCDO said it released details of the exchange publicly over fears it could be “manipulated”.
Two more government ministers were targeted in 2022, by an imposter pretending to be Ukraine’s prime minister between 2020 and 2025, Denys Shmyhal.
Defence Secretary Ben Wallace blamed Russian “dirty tricks” for the calls, made via Microsoft Teams, which Home Secretary Priti Patel confirmed she also received.
At the time, a Ministry of Defence source said the video call was “fairly sophisticated” and came via “another government department”, which added to its credibility.
