The head of MI5 has warned of a “new era” of threats from terrorists and enemy intelligence agencies.
Sir Ken McCallum admitted that spies working on behalf of Russia, China and Iran are targeting “our Parliament, our universities, [and] our critical infrastructure”.
MI5 has foiled 20 potential assassination plots ordered by Iran in the last year and warned of “Russian thugs” who are “committed to causing havoc and destruction”.
The number of state-threat investigations has surged by 35%, Sir Ken revealed.
Meanwhile, intelligence officers are dealing with a “near record” number of terrorism investigations, Sir Ken said.
The Director General said: “MI5’s fight against terrorism remains intense: my teams are currently running near-record volumes of investigations.
“But we are also having to contend with a second menace of equal or even greater scale, in fast-rising state threats.
“In 2025, a more hostile world is forcing the biggest shifts in MI5’s mission since 9/11.
“In the last year, we’ve seen a 35% increase in the number of individuals we’re investigating for involvement in state threat activity.
“That means espionage, including against our Parliament, our universities, our critical infrastructure.
“But now, states are also consistently descending into ugly methods MI5 is more used to seeing in our terrorism casework.
“My teams are routinely uncovering attempts by state actors to commission surveillance, sabotage, arson or physical violence, right here in the UK.”
And Sir Ken, in an alarming admission about the threats facing the UK, said Al Qaeda and Islamic State are “once again becoming more ambitious”.
Since 2020, 19 late-stage attack plots have been foiled.
Extremists living abroad are both “personally encouraging and indirectly inciting would-be attackers in the West.”
Outlining the terror threat to the UK, Sir Ken said: “MI5’s fight against terrorism remains intense: my teams are currently running near-record volumes of investigations.
“Since the start of 2020, MI5 and our police partners have together disrupted 19 late-stage attack plots. And we’ve intervened in many hundreds of developing threats.
“On average, our investigations tend to be narrower in scope than once was the norm: my teams are mostly focused on individuals or small groups, rather than larger, more established networks.
“But the aggregate scale of the terrorism threat remains huge. And the range of what’s coming at us – from terrorists holding Islamist, Extremist Right Wing or other ideologies, just keeps growing.
“Groups overseas are continuing their attempts to direct terrorism into the UK and Europe.
“Al Qaeda and Islamic State are once again becoming more ambitious, taking advantage of instability overseas to gain firmer footholds.
“They are both personally encouraging and indirectly inciting would-be attackers in the West.
“Terrorism breeds in squalid corners of the internet where poisonous ideologies, of whatever sort, meet volatile, often chaotic individual lives.
“The online environment can blur motive, too. Some situations are clear-cut. But it’s often messier. In 2025, it can be hard to tell in the immediate aftermath of an appalling violent crime whether the incident is terrorist or state-directed, and thus a national security matter, or non-ideological, driven by a unique grievance, fixation or mental disturbance.
“We are particularly conscious of these complexities when it comes to vulnerable young people.
“Sadly, we continue to see a concerning number of minors in our national security investigations: one in five of the 232 terrorism arrests last year were of children under 17.”
But Sir Ken spent much of his annual state threat assessment talking about Russia, China and Iran.
Speaking at MI5’s headquarters in London, he said: “I spoke twelve months ago about rising aggression on UK soil.
“Data on MI5’s operations extends that worsening trend. State threats are escalating.”
The Director General again warned Moscow’s intelligence agencies are “picking up what they can online”, attempting to recruit criminals to carry out arson, kidnap and sabotage conspiracies.
Revealing new details about the hiring campaigns, the top spy said Russia approaches people on social media platforms, sends instructions on encrypted messaging apps and offers payments using cryptocurrencies.
But the GRU and FSB are not paying those they order to carry out their dirty work, Sir Ken said.
He added: “In the last year, we and the police have disrupted a steady stream of surveillance plots with hostile intent – aimed at individuals Russian leaders perceive as their enemies.
“We’re seeing Russia-based figures using online platforms in wider attempts – largely unsuccessful – to sow the seed of violence, chaos and division here in the UK.
“I can’t itemise our most recent disruptions. But you already know that six individuals were convicted in May for carrying out a range of malign activities in the UK and across Europe.
“The orders were Russian, but the foot soldiers were not highly trained Russian operatives. Or even poorly trained Russian operatives.
“They happened to be Bulgarian nationals, motivated by money and the thrill of playing spies.”
Turning to those being hired by the Kremlin’s spies, Sir Ken warned “you are disposable” to Moscow.
He added: “You may well be ghosted on payday. When you’re caught, you’ll be abandoned. You won’t feature in a prisoner exchange. You’re on your own.
“With our partners across Europe, MI5 will keep detecting those who take orders from Russian thugs. And we will keep following the trails back to those giving the orders, who imagine they’re anonymous and unfindable behind their screens. They’re not.”