British Prime Minister Andy Burnham exchanged messages with an impostor posing as White House Chief of Staff Susie Wiles, triggering a national security investigation.
Burnham initially communicated with the individual under the belief that the contact was authentic before becoming suspicious that something was wrong, according to a report by Politico.
Four officials confirmed to the news outlet that an exchange of messages took place between the leader and the unidentified sender. Downing Street declined to provide further details, stating that it does not comment on national security matters.
A person briefed on the communications said the prime minister exchanged a small number of messages with the unknown sender after taking office at Downing Street. The same source insisted that the content of the exchange had no significance, though they did not disclose what was discussed.
It remains unclear precisely when the communication began or how long Burnham believed he was conversing with Wiles. The matter was kept as a closely guarded secret within the British government due to its sensitivity and concerns over security.
Diplomatic contact and security fears
The incident raised sufficient alarm that the British Embassy in Washington raised the issue directly with the White House, according to two officials who spoke to Politico.
10 Downing Street serves as the official residence and executive office of the British prime minister in London, while the British Embassy in Washington handles diplomatic relations between the United Kingdom and the United States. Communication channels between the two allied governments are typically subject to rigorous security protocols.
Inside the British government, officials initially feared that the telephone or contact list belonging to Wiles had been compromised again. However, the White House rejected that possibility, with an official from the US presidency stating that the incident had nothing to do with a breach of the chief of staff's devices.
Susie Wiles serves as one of the closest advisers to US President Donald Trump. As White House chief of staff, she manages executive operations, controls access to the president, and oversees high-level government communications in Washington.
Previous impersonation attempts
The incident caused particular concern in London because it is not the first time an unknown individual has impersonated the senior American official. The previous year, the White House and the Federal Bureau of Investigation launched a joint investigation after US senators, state governors, and top corporate executives received phone calls and text messages from someone claiming to be Wiles.
At the time, The Wall Street Journal reported that Wiles had informed her associates that the contact list stored on her mobile phone had been compromised.
The Federal Bureau of Investigation is the principal domestic intelligence and federal law enforcement agency of the United States. Politico and The Wall Street Journal are major American political and financial news publications that cover federal governance and national security affairs.
Unanswered questions and federal warnings
It is not currently known what specific information was contained in the messages exchanged with Burnham, nor whether the impostor requested any information or specific actions from the British leader.
The FBI had previously issued a warning on May 15, 2025, regarding an ongoing campaign in which malicious actors impersonated senior US government officials using text messages and voice messages potentially generated using artificial intelligence. The agency emphasized that anyone receiving communications from a supposed high-ranking official should not assume the messages are authentic.
Artificial intelligence technologies can mimic human voices and generate realistic text messages, presenting automated security risks for high-profile figures. Security agencies advise public officials to verify unsolicited digital communications through established secondary authentication channels.
