The head of MI5 vowed to “never back off” from confronting Chinese spies as he told of his frustration over the bungled prosecution of two alleged moles.
Sir Ken McCallum said China poses a threat “every day” as they try to steal state secrets, academic research, business information and harass and kidnap dissidents living in the UK.
Sir Ken also stressed that Chinese “state actors” posed a threat “last year and the year before that” and will “next year”.
British intelligence officers foiled a suspected Chinese spy plot in the past week, Sir Ken revealed.
It comes as the Director General of Britain’s domestic intelligence agency revealed a 35% increase in state threat investigations.
The Director General of MI5 said in his annual state threat assessment: “MI5 will keep doing what the public should expect of us: preventing, detecting and disrupting activity of national security concern.
“Our track record is strong. We’ve intervened operationally again just in the last week.
“I am MI5 born and bred. I will never back off from confronting threats to the UK, wherever they are from.”
Sir Ken added: “Do Chinese state actors present a UK national security threat? The answer is, of course, they do, every day.
“I said that last year, I said it the year before, I said it the year before that.
“If I’m in this job a year from now, I’m sure I will say it then too.”
The two men accused of spying for China allegedly gave sensitive information to a Chinese intelligence agent for around a year.
Former parliamentary researcher Christopher Cash and his friend Christopher Berry both denied passing secrets to China before the case was dropped by the Crown Prosecution Service (CPS) in September.
The pair were accused of handing an intelligence agent details about the inner wokring of the British political system and the Government’s position on Chinese businesses.
This was then handed to a senior member of the Chinese Communist Party and a Politburo member.
Deputy national security adviser Matt Collins, whose witness statements were published on Wednesday, said sensitive information relating to the personal and political activities of MPs was also allegedly passed between the two men.
These included Jeremy Hunt being likely to pull out of the Conservative Party leadership race and Tom Tugendhat being “almost certain” to get a cabinet position from then-prime minister Rishi Sunak in exchange for support on foreign policy matters.
Mr Collins said a meeting between Mr Berry and a senior Chinese Communist Party (CCP) leader in July 2022 was “highly unlikely” to have happened “unless the Chinese state considered him to be someone who could obtain valuable information”.
Mr Collins said Mr Cash was made aware “in detail” of the July 2022 meeting, with the researcher allegedly sending Mr Berry a message which read: “You’re in spy territory now.”
The CPS alleged the intelligence agent commissioned at least 34 reports from Mr Berry, which included information obtained from Mr Cash following the agent’s requests for reports on specific topics.
And the head of MI5 admitted he is frustrated the case collapsed.
He told reporters: “Of course I am frustrated when opportunities to prosecute national security threatening activity are not followed through.
“The activity was disrupted. MI5’s job, distinctively, is to detect and disrupt threats to UK national security and I’m pleased with how my teams have been doing that.
“Alongside our work, sits this adjacent swim lane of bringing prosecutions through the criminal courts.
“Sometimes MI5 contributes to those prosecutions, but that is not really our own trade.
“It is far more unprecedented for us to brave disruptive action that mitigates threat to UK national security and for that, not then in every single case to result in a criminal conviction.
“We obviously like it when it does, if we think that is the best way of ensuring an enduring disruption but that’s not something that is always possible for a whole host of different reasons.
“So my teams have every right to feel proud of the detection and disruption job that they have done in this case and in a whole series of other cases.
“Clearly, when we believe there has been activity threatening UK national security, convictions are great, we work very hard with our police colleagues to make those possible.
“So it’s frustrating when they don’t happen. But I would invite everyone not to miss that this was a strong disruption in the interests of the UK’s national security.”
Mr Collins’s witness statement added that the alleged information-sharing system “emboldens the Chinese state to believe that it is possible to successfully penetrate the UK’s institutions and may encourage them to make further efforts to do so”.
Going further on Chinese intelligence operations, Sir Ken said: “Try not to think too much just in terms of classic kind of card carrying spies out of embassies from the Le Carre mould.
“What we often see is information, not all of which is state secret, but some of which will be industrial advantage, it will be university basic research, especially around technology, we see a whole host of ways in which Chinese state actors are able to collect information of value to them.”
And he defended Mr Collins as questions intensified over whether he had political instructions to stress how Labour wanted an economic relationship with Beijing.
Sir Ken said: “I try quite hard not to get into personality things. But I might just allow myself to make a rare exception.
“I’ve obviously worked for a number of years in adjacent roles alongside Matt Collins. I do consider him to be a man of high integrity and a professional of considerable quality.”
The head of MI5 said a strong relationship with China gives the Government a better “position” to push back.
“When it comes to China, the UK needs to defend itself resolutely against security threats and seize the opportunities that demonstrably serve our nation.
“Our 5Eyes allies share the same pragmatic approach. The policy choices lie in exactly which lines you draw, which balances you strike.
“Those choices are for government, informed by expert security advice.
“Whatever the policy choices, just on security grounds, there are good reasons for maintaining a substantive relationship with China.
“When lines are crossed, being seriously engaged gives the UK a stronger position from which to push back.”