Having been radicalised by the ever-growing torrent of online jihadist propaganda, a new and unprecedented wave of would-be murderers, most still in their teens, go on to perpetrate real-world violence, with Jews as their principal targets.

Now, security experts say, this social media-savvy group pose a deadly threat to the crowning event of the summer: the Paris Olympic Games.

Since the October 7 massacre by Hamas, the JC can reveal, police in Britain and western Europe have detained 61 alleged Islamist terrorists accused of 28 separate plots, which were either successfully executed or thwarted at an advanced stage.

Almost two-thirds of these suspects, no fewer than 40, were aged 19 or younger when they were arrested, and the youngest was just 14.

It is thought that most had viewed some of the thousands of antisemitic and pro-terrorism videos that have been posted since October 7 on platforms such as X/Twitter, Telegram and TikTok.

Only last week, a UK court was told that posts on TikTok were responsible for radicalising Mohammad Farooq, a trainee nurse found guilty of trying to blow up the hospital where he worked, St James’s in Leeds.

Suspects recently arrested across Europe include a boy of 15 awaiting trial for the near-fatal stabbing of an Orthodox Jewish man on his way home from a Zurich synagogue on March 3. According to eyewitnesses, the perpetrator shouted “death to all Jews” as he carried out his attack.

Peter Neumann, professor of security studies at King’s College, London, told the JC that the suspects’ ages made their emergence “a totally new phenomenon”. In the past, he said, “the odd teenager would be arrested for terrorism once in a while, and we were shocked, because it was exceptional. Not any more.”

Neumann who coined the term “TikTok terrorists”, and last month he briefed the French Interior Ministry about the dangers posed by teens radicalised on social media. He said: “It starts with them sharing videos and egging each other on, and then they get together and decide to do something, to plan a terrorist attack.”

Much of the content being viewed online comes directly from the propaganda departments of terror groups such as Hezbollah, Hamas, Islamic State and al-Qaeda. Often, the videos being posted daily even bear their official logos.

It is not difficult for such groups to see who is following them. According to Neumann, regular viewers of jihadist material are being spotted as potential recruits, then guided towards hidden sites on the dark web, where they can be “groomed” and given online training on how to commit and conceal an attack.

After Farooq was convicted of planning his attack in Leeds, police said the bomb he was carrying was inside a pressure cooker and he had learnt to make it from accessing terror sites on the internet. They said it was twice the size of the device that killed three and injured hundreds at the 2013 Boston marathon. If he had managed to detonate it, it would have caused “significant loss of life”.

Farooq, who will be sentenced at a later hearing, was 27 when he was arrested last year – a few years older than most members of the new wave of terrorists threatening Europe. Nevertheless, his case is an object lesson in the threat posed by ‘TikTok terrorism’: the evidence heard in court showed that before he prepared his attack, he had watched dozens of the platform’s videos pushing jihadist and antisemitic messages.

In one, an imam told viewers: “With the sword, Islam is established, forcing them to accept the religion. Don’t be shy of being called a terrorist. Yes, we are terrorists.”

Others referenced the 7th-century massacre of Jews by a Muslim army at Khaybar in Arabia juxtaposed with images of the al-Aqsa mosque in Jerusalem; another was entitled “Jewish people say the Jews will control the world”.

Researchers at the Centre for Countering Digital Hate have found that antisemitism is rife on TikTok, uncovering 10 separate hashtags containing antismitic videos that have been watched more than 53 million times. These include #germanreich, a repository for videos idolising Hitler; and #gnomehuntingeurope, which posts videos, some picturing deadly weapons, about “hunting gnomes and killing them”. There is no secret who are the “gnomes”: in the words of one commenter on the TikTok site, “the gnomes represent the Jews”.

Since the JC spoke to TikTok on Monday it has removed four of the antisemitism-related hashtags, but others remain.

Since October 7, the X/Twitter platform has featured several accounts with up to a million followers each that openly post terrorist propaganda videos numerous times a day. X’s new owner Elon Musk’s decision to abandon content moderation means no attempt has been made to remove them.

Three of these accounts, Suppressed News, War Monitor and Warfare Analysis, contain videos that appear to have been shot just hours or even minutes earlier by members of Hamas and Hezbollah.

One example last week showed an Israeli armoured vehicle – described by War Monitor as a “Jewmobile” – coming under attack.  

Another showed the shooting of an IDF soldier somewhere in Gaza with a red triangle – a symbol widely used by Hamas supporters  –superimposed on the video and pointing at the soldier’s head before he was killed.

Another video posted by all three accounts last Wednesday depicted the murder of off-duty soldier Sergeant Aleksandr Iakiminskyi earlier that morning at a shopping mall in Karmiel in the northern Israel. War Monitor described the recording as a “video from the stabbing operation in the Galilee this morning, Zionist soldier was killed swiftly”.

The same account praised Hamas’s killing of “two Zionist terrorists” later the same day in Gaza, featuring photos of the deceased.

Other videos from these accounts, which also post on Telegram, contain horrifying images of dead Palestinians, accompanied by text suggesting all were innocent victims of Israel’s “genocide”.

Sites controlled by both Isis – especially its Afghan branch, known as Isis Khorasan Province – and al-Qaeda warmly praised the October 7 massacre. According to Marc Hecker, a French terrorism expert and deputy director of IFSR, the French Institute of International Relations, they were “ecstatic” about the attack, and al-Qaeda issued a series of communiqués supporting it.

A few days after the Gaza war started, Naba, the online magazine of Isis, published an article in several languages under the headline “Practical Steps to Fight the Jews”.

“Young Muslims must prepare themselves and be equipped with whatever military equipment is available to them”, the article said, until “the Jews reach the point where they find nothing to take refuge in and hide behind except stones and trees, [and] realise that they have not lived through the Holocaust yet!” 

The first terrorist attack in Europe after October 7 took place less than a week later, on October 13, when a Muslim Russian aged 20 went on the rampage at a school in Arras in Normandy, fatally stabbing a teacher, Dominique Bernard, and seriously injuring three others.

Two days later, Moroccan asylum seeker Ahmed Alid, 45, roamed the streets of Hartlepool, looking for someone to murder in what he later told police was “revenge” for Israel’s response to the massacre. He killed a man of 70 by stabbing him multiple times, and also attacked his flatmate, wounding him severely.

The judge at his trial, who sentenced him to life in May with a minimum term of 44 years, said his crimes were a “terrorist act” by which he hoped to “influence the British government” to end its support for Israel.

These and other successful attacks, such as the Zurich stabbing and a knife attack in Paris on December 2 by a supporter of Isis that left one person dead and two severely injured, have been widely reported. However, other plots – especially those involving very young conspirators – have not. One of the most concerning, Neumann said, was a plot to attack Le Botanique, a concert venue in Brussels, in a copy of the shooting rampage that left 90 dead at the Bataclan hall in Paris in 2016.

Its 11 alleged members, arrested in March and April, were all aged 18 or under; four were just 15.

All the members of this “virtual terrorist cell” spoke French, but they spanned three countries, France, Switzerland and Belgium. Neumann told the JC that they met each other online and set up a Telegram group, where at first they merely shared jihadist propaganda and Isis videos.

However, “at the beginning of 2024, the group’s purpose changed: suddenly it was about carrying out an attack”.

The Belgians selected the target and carried out a reconnaissance. The arrests were made when they began to take steps to acquire Kalashnikovs from a Belgian criminal network to which they had been introduced by a man in Switzerland.

A conspiracy involving seven German speakers aged 15 to 18 from Germany and Switzerland was thwarted in April. It too was based on a Telegram group, led by a girl from Dusseldorf, who was just 15, whose father was known to the authorities as a supporter of Isis. Its intended targets included bars, churches and a synagogue in the town of Iserlohn.

France has made clear that the security operation designed to protect the Olympics will be enormous.

Since the jihadist attack on the Crocus concert hall in Moscow that killed 143 people in March, the French Interior Ministry has put the country on its highest alert level, which Hecker said is normally used only when the perpetrators of an attack are still on the loose.

On the night of the opening ceremony, Hecker went on, there will be 35,000 police and gendarmes on duty, 10,000 troops and 10,000 private security men, with at least 30,000 on duty throughout Games.

“If they get any kind of intelligence, there will be arrests,” Hecker said, “and it will very hard to get into any of the Olympic sites with a weapon.”

On the other hand, he admitted, “it could still happen”. Trying to safeguard the opening ceremony, a procession of barges for several miles down the Seine, each containing a national team, may prove to be challenging.

Meanwhile, an Isis communiqué issued on Halummu, a website allied to the terror group which posts in English, bears the headline “To the stadiums”. “Launch, O Muwahhhid, to your new target,” it goes on.

A Community Security Trust spokesperson told the JC: “The amount of jihadist propaganda and anti-Jewish incitement on social media platforms is staggering and poses a clear danger, and this is not a new problem. Tech companies have had years to find a way to prevent their platforms being used to incite terror and hatred, and the fact that it is still so prevalent is damning proof that they haven’t done enough to take effective action. At a time of heightened anti-Jewish hatred and with the threat of terrorism facing Jewish communities and wider society, there is an urgent need for governments and police to act.

X was approached for comment.

A Telegram spokesperson said: “Telegram's efforts to remove terrorist propaganda have resulted in the removal of millions of pieces of content,” saying that the platform had been working with counter-extremism experts and had removed 18.6 million posts in the second quarter of 2024 alone. 

A TikTok spokesman said: “Hateful ideologies, like antisemitism, are not and have never been allowed on our platform. We remove 91 per cent of content found to break these rules before it is reported to us, work with the World Jewish Congress to remove content and have some of the fewest online antisemitic incidences according to the CST.” ​