MI5, Britain’s domestic intelligence and security agency chief, Ken McCallum, said that the threat of terrorism from the far right is comparatively really quite small compared to the Islamic terror threat, which is the main threat facing this country.

The Guardian McCallum warned in his annual update that the greatest concern was a worsening threat from al Qaeda and the Islamic State (ISIS). While ISIS is not as strong as a decade ago, he said MI5 and many of its European partners were detecting ISIS-connected activity. Of MI5’s counter-terrorism work, 75% was focused on Islamic extremists.

McCallum said a revival of ISIS in Afghanistan in particular had brought a resumption of efforts by the Islamist group to export terrorism, and a “bit of an upswing” in Britons seeking to travel abroad to learn from the group.

McCallum said the “worsening threat” from ISIS and, to a lesser extent, al-Qaeda, was “the terrorist trend that concerns me most” and he noted that al-Qaeda had “sought to capitalize on conflict in the Middle East” in its calls for violent action. “Over the last month, more than a third of our top-priority investigations have had some form of connection, of varying strengths, to organised overseas Islamic terrorist groups,” he said as he gave a threat update.

Spy chiefs are focused on the revival of ISIS’s Afghan affiliate, Islamic State Khorasan Province (ISKP), which has grown in strength after the western withdrawal from Afghanistan. It claimed responsibility for the deadly attack in Moscow in March where militants opened fire at a concert, killing 133 people and wounding 140.

Two brothers from Birmingham were sentenced last November for trying to travel to Afghanistan to join ISKP, McCallum noted. They received jail terms of 10 years and eight years.

The spy chief said it was not the case that Israel’s ongoing war with Hamas in Gaza and Hezbollah in Lebanon had led directly to an increase in terrorist plotting in the UK, though he acknowledged there had been “rising public order, hate crime and community safety challenges” that police had had to deal with.

Terror threats tended to develop over a long period, he added. “The ripples from conflict in that region will not necessarily arrive at our shores in a straightforward fashion,” he said, but the UK terror threat remained unchanged at “substantial”, the third level on a five-point scale.

McCallum highlighted that Iran had been behind “plot after plot” in the UK in the past two years. Five new Iran-backed plots have been uncovered by MI5 and police this year, taking the total since January 2022 to 20. Iranian state actors made “extensive use of criminals as proxies”, to try to carry out threats and intimidation largely directed against dissidents and individuals perceived as a threat to the Tehran regime.

He said MI5 was alive to the possibility that Iran “could, in principle, try to repurpose” that effort to focus on other targets in the UK if Tehran felt that Britain had become a party to the conflict in the Middle East by supporting Israel.

The number of late-stage terror plots disrupted since March 2017 had increased to 43, McCallum said. The last time the spy chief gave a comparable figure it was 37 in November 2022, meaning six plots have been prevented in nearly two years.

Radical Islam is the snake in the grass, moderate Islam is the grass the snake hides in. And it isn’t just Islamic terrorism which is the biggest threat. The radical beliefs of too many Muslims in the UK make them uniquely incapable of assimilating into the British culture.