MI5 thwarted Chinese plot to attack Britain’s national security last week as spy chief says UK ‘needs to up its game’ against outside threats

MI5’s spy chief revealed today that he had foiled a Chinese plot to attack Britain’s national security, as he revealed his disappointment at the collapse of the spy case.

Sir Ken McCallum vowed today to “never back down from confronting threats to the UK” after a critical spying case collapsed after the government refused to designate Beijing as an enemy of Britain.

After weeks of accusations that Sir Keir Starmer was ‘too weak’ on China, the intelligence chief called on the Government to ‘ensure the UK is a difficult target’, adding: ‘We need to up our game.’

In his annual threat speech, Sir Ken warned that there has been a 35 per cent increase in hostile state threat activity targeting the UK and new plots and threats are being detected ‘every day’, revealing that a major Chinese espionage plot was foiled just last week.

In an unprecedented intervention, the Director-General chose to break the long-standing tradition of MI5 not commenting on individual cases as he expressed his disappointment that parliamentary investigators Chris Cash, 30, and Chris Berry, 33, had not been prosecuted for allegedly passing secrets to Beijing.

‘Of course, I am disappointed that opportunities to prosecute activities that threaten national security are not pursued, for whatever reason,’ he said.

But Sir Ken pointed out: ‘I’m sure you have in mind the specific case in which activity was disrupted’ and added that his team ‘have every reason to be proud of the detection and disruption job they did in this case’.

He said: ‘Obviously when we believe there is activity that threatens the national security of the UK, convictions are great, we work hard with our police colleagues to make them possible and so it’s frustrating when they don’t. I urge everyone not to lose sight of the fact that this is a powerful disruption to the UK’s national security.’

Speaking at Thames House, Sir Ken said: ‘I am MI5, born and bred. ‘I will never shy away from countering threats to the UK, wherever they come from.’

He said Britain needs to ‘defend itself resolutely against threats’, adding: ‘In this new era, with multiple overlapping threats on an unprecedented scale, we need to up our game.

‘We cannot rely on investigation and disruption alone. Together we must ensure that the UK is a difficult target.

‘We want our enemies to think twice before moving against us.’

Sir Ken pointedly said there were ‘policy choices’ for the Government that determined ‘exactly what lines you draw, what balances you strike’.

He warned that MI5 was in a ‘new era’ of unprecedented threats: ‘In 2025, MI5 is dealing with more voluminous and more diverse threats from terrorists and state actors than I have ever seen before.’

He also spoke of ‘increasing aggression on British soil’.

‘State threats are increasing’ Last year, we saw a 35 percent increase in the number of people we investigated for alleged involvement in state threat activities,’ he said.

‘This amounts to espionage against our Parliament, our universities and our critical infrastructure.

‘But now states are constantly turning to the ugly methods that MI5 is more accustomed to seeing in terrorism cases.

‘My teams routinely uncover attempts by state actors to carry out surveillance, sabotage, arson or physical violence right here in the UK.

‘We deal with these threats every day.’

Sir Ken McCallum speaks to journalists at the annual Director-General’s Address in London today

MI5 tracked down more than 20 potentially lethal Iran-backed plots last year.

Sir Ken told how MI5 is struggling with ‘near record’ terrorism investigations and added: ‘In 2025, a more hostile world is forcing the biggest changes to MI5’s mission since 9/11.’

MI5 has foiled 19 late-stage terror plots and responded to ‘hundreds of evolving threats’ since 2020.

The spymaster warned that Al Qaeda and the Islamic State are becoming “more ambitious” to recruit young people in “dirty corners of the internet” where poisonous ideologies lurk.

Asked directly whether China poses a national security threat, Sir Ken said: ‘Do Chinese state actors pose a threat to the UK’s national security?

‘And the answer of course is yes, they do it every day.’

But he defended the Government’s deputy national security adviser, Matt Collins, who refused to say China was a national security threat, which led to the collapse of the espionage case against Mr Cash and Mr Berry in September.

Sir Ken described Mr Collins as ‘a man of high integrity and a highly qualified professional’.

The MI5 chief said he would not like the number of people involved in Beijing’s operations targeting Britain, telling reporters: ‘Try not to think of it too much as classic, card-carrying spies based out of embassies in the Le Carre mould.’

He said there are ‘many ways that Chinese state actors can collect valuable information for themselves.’