MI5 Director-General, Sir Ken McCallum, has warned that Chinese state operatives pose a daily national security threat to the United Kingdom.
In a speech delivered this week, Sir Ken revealed that MI5 had “intervened operationally” to disrupt Chinese activities of concern within the past seven days.
Addressing the controversy surrounding the collapse of a major UK spying case linked to China, he said the agency had successfully disrupted the alleged activity but found it “frustrating when prosecutions fall through.”
The government and the Crown Prosecution Service are now under scrutiny after dropping the case last month, citing insufficient evidence that China represented a national security threat.
However, witness statements from Deputy National Security Adviser Matthew Collins, released on Wednesday, contradicted that stance, asserting that China was engaged in “large scale espionage” and remained “the biggest state-based threat to the country’s economic security.”
Sir Ken described Collins as “a man of high integrity and a professional of considerable quality.”
He reiterated that “Chinese state actors” pose a real threat to Britain’s national security, though he added that balancing relations with China “is a matter for the government.”
“When it comes to China, the UK needs to defend itself resolutely against threats and seize the opportunities that demonstrably serve our nation,” Sir Ken stated.
The case’s collapse has triggered a political storm. Conservatives accuse the Labour government of allowing it to fail to protect economic ties with Beijing.
Downing Street rejected those claims, calling it “absurd” to suggest the Prime Minister should have interfered in what it described as an independent criminal matter.
In a strongly worded letter to the Prime Minister, Conservative leader Kemi Badenoch said the episode “leaves a strong impression that your government undermined Britain’s national security because you are too weak to do anything other than appease China.”
Responding, Sir Keir Starmer argued the prosecution hinged on how China was viewed by the then Conservative government between 2021 and 2023.
“In other words,” he said, “the prosecution’s case required demonstrating that the position of the then Conservative government was that China was an enemy of the United Kingdom,” which he called “plainly wrong.”
CPS Director Stephen Parkinson has also come under fire, with MPs claiming there was enough evidence to let a jury decide. Parkinson reportedly told senior lawmakers the case was “5% short” of the evidence threshold needed for conviction.
Conservatives have since written to the CPS, demanding to know what additional evidence was requested from the government.
Labour MP Matt Western, chair of the Joint Committee on the National Security Strategy, announced an inquiry into why the case collapsed.
The original investigation targeted former parliamentary researcher Christopher Cash, 30, and academic Christopher Berry, 33, accused of collaborating with a senior figure in China’s Central National Security Commission, chaired by President Xi Jinping.
In one message, Cash allegedly told Berry, “You’re in spy territory now.” Both men deny any wrongdoing.
Collins’ February 2025 witness statement, submitted after Labour took office, warned that Chinese espionage threatened “the UK’s economic prosperity and resilience.”
A third statement, published in August, reaffirmed that threat but noted the government’s aim to maintain “a positive economic relationship with China.”
Responding to the controversy, Chinese Foreign Ministry spokesperson Lin Jian said: “China’s position is very clear: we firmly oppose peddling China spy narratives and vilifying China.”
Former Security Minister Tom Tugendhat, who once employed Cash as a researcher, accused the government of prioritizing process over protection. “Who the hell’s side are you on?” he demanded during a Commons debate.
Cash later said he had been placed in an “impossible situation” by the absence of a public trial, adding, “The statements that have been made public are completely devoid of the context that would have been given at trial.”
Meanwhile, Conservative MP Alicia Kearns noted that Collins’ phrasing in his final statement — “we will co-operate where we can, compete where we need to, and challenge where we must”, was identical to a line from Labour’s manifesto, raising suspicions of political influence.
“In my view, the Crown Prosecution Service should have proceeded with this,” Kearns said. “The case law shows it’s for a jury to decide if China is or could be a threat to our country.”
Sources close to the investigation told the BBC that Collins believed his August statement contained sufficient evidence for the CPS to continue. The CPS had requested clarification after his first submission but reportedly did not specify what was required to meet its threshold.
The Director of Public Prosecutions later explained that while the evidence had initially been sufficient for charges, a precedent set by another espionage case earlier in the year required China to have been explicitly designated a “national security threat” at the time of the alleged offences.
Liberal Democrat foreign affairs spokesperson Calum Miller said the revelations left “yet more unanswered questions,” adding, “We clearly need a statutory public inquiry to get to the bottom of this whole fiasco.”
