ISIS is back, says UK spy chief 

LONDON — ISIS has resumed its efforts to export terrorism to Britain, the head of the U.K.’s domestic spy agency has said, as he warned it is the threat that “concerns me most.” 

Ken McCallum, the director general of security service MI5, on Tuesday gave the U.K.’s first threat update since 2022, offering a wide-ranging assessment of threats from the Middle East, Russia — and much closer to home.

He warned that there is now an increased threat of terrorism from al Qaeda “and in particular” from ISIS, also known as Islamic State and Daesh. The group burst into the international consciousness in 2014, when its militants took over large parts of northwestern Iraq and eastern Syria.

“Today’s Islamic State is not the force it was a decade ago, but after a few years of being pinned well back, they’ve resumed their efforts to export terrorism,” he told a press conference in central London.

McCallum pointed to the deadly March concert hall attack in Moscow, carried out by offshoot ISIS-K, as a “brutal demonstration of its capability.” 

The MI5 boss, whose agency oversees domestic counter-intelligence, said that over the last month alone more than a third of MI5’s top priority investigations had “some form of connection … to organized overseas terrorist groups.” 

Russia and China

McCallum also used his London appearance — rare for a U.K. intelligence boss — to warn about the growing malign influence of Russia and Iran on U.K. soil and take aim at “heightened state aggression” from the pair.

He said the number of MI5 investigations into hostile states such as Russia and Iran had risen by almost half in a single year. Russian intelligence agency the GRU is, he said, on a “sustained mission to generate mayhem on British and European streets.” 

Over 750 Russian diplomats — “the great majority of them spies” — have been expelled from Europe since Vladimir Putin invaded Ukraine, he said. The U.K expelled what it believes to be the last remaining Russian military intelligence officer from the country earlier this year. 

And yet the threat has emerged elsewhere. Europe’s’ tactic of “kick them out, keep them out” when it comes to intelligence officers had, McCallum made clear, led to an increased reliance on cyber-attacks from Russia.

This year has also seen an increase in the use of proxies such as private intelligence operatives and criminals inside the U.K. and abroad to do the “dirty work” of hostile states, he said.

In a message to would-be criminals prepared to take money from Iran or Russia to carry out illegal acts in the UK, he said: “It’s a choice you’ll regret.” 

He described Iran’s threat to Britain as increasing at an “unprecedented scale and pace” and said the U.K. had responded to twenty “potentially lethal” Iran-backed plots since 2022.

McCallum was notably less hawkish on China, as debate rages in British politics about how best to approach Beijing. “China is different,” he said. “The U.K.-China economic relationship supports U.K. growth, which underpins our security.” 

When asked about an apparent lack of criticism of Beijing, McCallum said he “had not intended to diminish” the importance of the threat from China and that MI5’s focus is “unaltered.” 

“The choices are complex, and it rightly falls to ministers to make the big strategic judgements on our relationship with China,” he said. 

Capacity questions

These combined threats have seen MI5 and the police disrupt 43 late-stage attack plots since March 2017, the intelligence boss said Tuesday. But he argued that the security services are currently stretched. 

With just over two weeks until the U.K.’s government-wide budget, McCallum said “allocating our finite capacity” is now “harder than I can recall in my career.” 

Responding to a question from POLITICO about whether MI5’s caseload is still too high, as suggested in 2022 by parliament’s security and intelligence committee, McCallum said: “Things are absolutely stretched.” 

“It is about accurate to say that the overall volume of counterterrorism work we are doing in MI5 today has been, broadly speaking, about static for the last four or five years,” he said. A reduction in Islamic State activity has been offset and exceeded by a rise in extreme right wing terrorism, he warned.

There has been a threefold increase in the last three years of MI5 casework involving people under 18 involved in terrorism. That now makes up 13 per cent of cases, he said.

MI5 “now have an uncomfortable life” deciding what to prioritize and what things “we just can’t get to,” adding: “That puts us under pretty sharp pressure.”