Two men were found guilty on Tuesday of plotting to kill hundreds in an Islamic State-inspired gun rampage against the Jewish community in England, a planned attack investigators say demonstrates the resurgent risk posed by the militant group.

Police and prosecutors said Walid Saadaoui, 38, and Amar Hussein, 52, who went on trial a week after an unrelated deadly attack on a synagogue in the nearby northwest city of Manchester in October, were Islamic extremists who wanted to use automatic firearms to kill as many Jews as they could.

Had their plans come to fruition, it would have resulted in "one of, if not the, deadliest terrorist attack in UK history", said Assistant Chief Constable Robert Potts, in charge of Counter-Terrorism Policing in northwest England.

Their convictions come little more than a week after a mass shooting at a Jewish Hanukkah celebration on Sydney's Bondi Beach in which 15 people were killed.

Islamic State said the Australian attacks were a "source of pride". Although the jihadist group did not claim responsibility, its response has heightened fears of an increase in violent Islamist extremism.

While not posing the same threat of a decade ago when Islamic State controlled vast areas of Iraq and Syria, European security officials caution that IS and affiliated al Qaeda groups are once again looking to export violence abroad, radicalising would-be attackers online.

"You can see signs of some of those terrorism threats starting to grow again and starting to escalate," British Foreign Secretary Yvette Cooper said last week.

Two men prepared to become martyrs

British prosecutors told jurors that Saadaoui and Hussein had "embraced the views" of Islamic State and were prepared to risk their own lives in order to become "martyrs".

Saadaoui had arranged for two assault rifles, an automatic pistol and almost 200 rounds of ammunition to be smuggled into Britain through the port of Dover when he was arrested in May 2024, prosecutor Harpreet Sandhu said.

He added that Saadaoui planned to obtain two more rifles, another pistol and collect at least 900 rounds. Unbeknown to him, a man known as "Farouk" he was trying to get the weapons from was an undercover operative, which police said meant his plan never came close to being put into operation.

Sandhu said the assault rifles Saadaoui wanted were similar to those used in a 2015 Islamist militant attack on the Bataclan concert hall in Paris that killed 130 people. He added that Saadaoui "hero-worshipped" Abdelhamid Abaaoud, who coordinated that attack.

Saadaoui said in a message to "Farouk", whom he thought was a fellow militant, that the Paris attack was "the biggest operation after that of Osama (bin Laden)", an apparent reference to the September 11, 2001 attack on the United States.

"Based on Walid's communications and interactions with the undercover operative, and some of the things he said, that made it very clear that he regarded a less sophisticated attack with less lethal weaponry as not being good enough," Potts said.

"Because, in effect, it was his role and his duty to kill as many Jewish people as he could, and that wasn't going to be achieved via the use of a knife or, for example, potentially a vehicle as a weapon."

Both Saadaoui and Hussein had pleaded not guilty and Saadaoui said that he had played along with the plot out of fear for his life.

Hussein did not give evidence and barely attended his trial after he angrily shouted from the dock on the first day "how many babies?" in an apparent reference to Israel's war in Gaza.

They were convicted in Preston Crown Court on a single charge of preparing terrorist acts.

Walid Saadaoui's brother Bilel Saadaoui, 36, was found guilty of failing to disclose information about acts of terrorism but prosectors said he had been reluctant to join the attack.

Islamic State threat growing

The foiled plot is the latest in Britain and elsewhere inspired by Islamic State, which emerged in Iraq and Syria a decade ago and quickly created a "caliphate", declaring its rule over all Muslims and largely displacing al Qaeda.

At the height of its power from 2014-17, Islamic State held swathes of the two countries, ruling over millions of people and imposing a strict, brutal interpretation of Islamic sharia law.

Its fighters also carried out or inspired attacks in dozens of cities around the world, which were often claimed by Islamic State even without any actual connection.

The SITE Intelligence Group said in the wake of the Bondi Beach attack in Australia that IS had encouraged Muslims to take action elsewhere, particularly singling out Belgium.

A European intelligence official, speaking on condition of anonymity, said IS was flooding social media with propaganda and while this impacted only a handful of people, it meant there were more terrorism investigations than last year.

Ken McCallum, head of Britain's domestic spy agency MI5, said in October that his service and the police had thwarted 19 late-stage attack plots since the start of 2020, and intervened to counter many hundreds of other terrorism threats.

"Terrorism breeds in squalid corners of the internet where poisonous ideologies, of whatever sort, meet volatile, often chaotic individual lives," McCallum said.