Chinese state-linked hackers reportedly accessed mobile phones “at the heart of Downing Street” as part of a long-running cyber-espionage campaign targeting telecom networks worldwide, according to Fox News.

U.S. intelligence agencies believe the breaches began as early as 2021, though they were publicly revealed in 2024 after American officials warned allies about widespread intrusions into global telecommunications systems.

The campaign targeted several countries, including the U.S. and members of the Five Eyes alliance. Investigators say the attackers may have gained access to the data of millions, with the ability to monitor calls, read messages, and track locations.

Former U.S. national security adviser Anne Neuberger said the “Chinese gained access to networks and essentially had broad and full access,” allowing them to “geolocate millions of individuals” and “record phone calls at will.”

Fox News reports that a source told The Telegraph that the breach reached “right into the heart of Downing Street,” raising concerns that senior U.K. officials may have been affected.

In response, U.S. agencies urged telecom companies in 2024 to strengthen security. A joint advisory in August 2025 warned that Chinese state-sponsored groups, including one known as “Salt Typhoon,” were continuing to target networks globally.

The Telegraph also reported “many” hacking incidents affecting British government phones, particularly during former Prime Minister Rishi Sunak’s term from 2022 to 2024.

Former Israeli intelligence chief Yuval Wollman said Salt Typhoon is “one of the most prominent names” in cyber-espionage, with operations extending across Europe, the Middle East, and Africa.

China has previously denied the allegations, calling them “baseless” and “lacking evidence.” U.K. officials have not yet commented on the latest reports.