Dominic Cummings, the former chief adviser to Boris Johnson, has ignited a political firestorm with allegations that China managed to compromise Britain’s most secure government data systems for years, stealing a trove of top-secret information. The claims, first reported by The Times and corroborated by other major UK outlets on October 15, 2025, have cast a harsh spotlight on the British state’s handling of national security and its delicate relationship with Beijing.
At the heart of Cummings’s accusations is the so-called “Strap” system, the highest-level classified data network used by the UK government. According to Cummings, this system—which is supposed to be airtight—was infiltrated by Chinese actors over a prolonged period. The breach, he says, allowed Beijing to harvest “vast amounts of data classified as extremely secret and extremely dangerous for any foreign entity to control.” This included intelligence agency data, documents from the National Security Secretariat, and other material that, if exposed, could have serious implications for British security and global intelligence operations.
“It was so bizarre that, not just Boris, a few people in the room were looking around like this: ‘Am I somehow misunderstanding what he’s saying? Because it sounds f------ crazy’,” Cummings told The Times, describing the moment in 2020 when he and then-Prime Minister Boris Johnson were first briefed on the breach by the cabinet secretary. He continued, “Vast amounts of data classified as extremely secret were compromised.”
The timing of these revelations is particularly sensitive. They coincide with the collapse of a high-profile Chinese espionage prosecution in the UK, in which two men—Christopher Cash and Christopher Berry—stood accused of passing sensitive intelligence from Parliament to the Chinese Communist Party. Both have denied the charges. The Crown Prosecution Service (CPS) ultimately dropped the case, citing the government’s refusal to officially declare China a national security threat at the time of the alleged offenses.
This decision has drawn sharp criticism from Cummings. He called the CPS’s stance “puerile nonsense,” insisting that “anyone who has been read in at a high level with the intelligence services on China knows that the word ‘threat’ doesn’t even begin to cover it.”
According to The Telegraph, the breach was so severe that a Cabinet Office inquiry was launched after Beijing acquired a company that controlled a data hub used by Whitehall departments to store classified information. While the Cabinet Office has officially denied that the systems used to transfer the UK’s most sensitive government information were compromised, sources did not dispute that external servers had been breached, nor could they rule out the possibility that sensitive information was involved.
One former Whitehall official dismissed Cummings’s account as “utter nonsense” but acknowledged that security breaches had occurred. The same source confirmed that then-Prime Minister Boris Johnson had commissioned a report from Lord Sedwill, his cabinet secretary and national security adviser, on how the Chinese had managed to buy a company so central to Whitehall’s data infrastructure.
Adding to the intrigue, four former government sources told The Spectator that two “very serious” scandals involving China and Russia had been “swept under the carpet,” with one case allegedly concealed to avoid embarrassing a former prime minister. “They hacked the Ministry of Defence and Downing Street,” one source claimed, attributing the most severe breach to Beijing’s acquisition of the Whitehall data hub.
Cummings also alleged a deliberate cover-up by senior officials. He stated that after he and Johnson were briefed in 2020, “officials from the Cabinet Office then went round telling everybody in the meeting that it was illegal for them to discuss this with the media.” He claimed to have been warned that disclosing certain details would constitute a criminal offense, particularly those involving “Strap” material. Cummings has now offered to provide details to Members of Parliament if a formal inquiry is launched.
What makes this story even more complex is the apparent tension between economic interests and national security. Cummings accused successive British governments of prioritizing trade and investment ties with China over the country’s own security. “The British state has prioritised Chinese money over its own security for decades,” he charged.
This accusation is reflected in recent government statements. In evidence submitted to the CPS concerning the collapsed spy case, Deputy National Security Adviser Matt Collins emphasized the UK’s commitment to a “positive economic relationship with China.” While Collins acknowledged that Chinese-linked cyberattacks and espionage “threaten the UK’s economic prosperity and resilience and the integrity of our democratic institutions,” he stopped short of labeling Beijing a national security threat, despite repeated requests from prosecutors.
Labour, now in power under Prime Minister Keir Starmer, has come under fire for its handling of the situation. Downing Street admitted that Starmer knew the Chinese spies case was on the brink of collapse two days before charges were dropped but did not intervene. This admission has fueled criticism from opposition parties and national security hawks, who argue that the government is still not being transparent about the scale of the breach or the extent of Chinese infiltration.
It is also unclear whether Starmer and his ministers were made aware of the alleged breach when they assumed office in July 2024. Some officials and political observers worry that the true extent of the compromise remains hidden, even from those now responsible for safeguarding the nation’s secrets.
The political fallout has been swift. Senior Tories have criticized the government for continuing business as usual with China, especially after the collapse of the spy trial. The Foreign Office’s top civil servant, Sir Oliver Robbins, traveled to China this week for meetings with business leaders and diplomats—a trip described as “long-planned,” but one that has raised eyebrows given the current tensions.
For now, the Cabinet Office stands by its denial. “It is untrue to claim that the systems we use to transfer the most sensitive government information have been compromised,” a spokesman said. Yet the questions raised by Cummings’s claims—and the corroborating accounts from multiple sources—are not likely to fade soon.
As the government faces mounting pressure to come clean about the breach and its response, the episode has become a litmus test for how Britain balances its economic ambitions with the imperative to protect national security in an era of increasingly brazen state-sponsored cyber-espionage. The coming weeks may force the government to make hard choices—and perhaps, at last, to fully reckon with the consequences of years of uneasy engagement with Beijing.
