The riots across England over the last week erupted abruptly but are linked to long-term efforts by an evolving UK far-right movement to weaponise anti-immigration sentiment to further their agenda, according to extremism experts.
Violence has hit more than a dozen places nationwide since last Tuesday, in the wake of a deadly knife attack on a group of children which authorities say far-right elements have used to whip up hate.
A British-born 17-year-old suspect, Axel Rudakubana, is accused of killing three young girls and attempting to murder another 10 people, including eight children.
Far-right agitators have used social media to spread racist, anti-Muslim and anti-migrant misinformation about him and the case in a bid to spark a violent backlash, according to officials.
The mobs, which have targeted hotels housing asylum seekers and injured dozens of police officers, are believed to be far-right ideologues, alongside "thugs" and disaffected youths harnessed in part online, authorities have said.
Experts on UK extremism note such tactics are among the new strategies of a far-right that has shifted online to compliment its traditional tactic of street violence.
"These are very often online networks of like-minded people rather than any sort of formal organisation," Milo Comerford, director of counter-extremism policy and research at London's Institute for Strategic Dialogue, told AFP.
"It is very much bringing together online mobilisation and activism with offline street movements and violence in this case."
'Fractured'
The UK has long had an active and violent far-right. The racist, anti-immigrant National Front emerged in the 1960s and 1970s -- associated with so-called skinhead culture -- and its offshoot British National Party gained prominence in the early 2000s.
The 2010s saw the emergence of new, more diffuse groups, with strong links to England's decades-old football hooligan scene. They included the anti-Islam English Defence League (EDL) and, more recently, the neo-Nazi Patriotic Alternative.
In recent years, such groups have tried to fuse mainstream right-wing concerns about levels of immigration with more extremist ideology, relying on loose organisational structures and social media to spread their message.
Far-right figures increasingly use "engagement" in disaffected communities, including direct action at immigration-related sites, to foment anti-migrant sentiment, according to experts.
In a 2021 paper focused on Patriotic Alternative, extremism academic William Allchorn noted that the UK far-right was incorporating this anti-migrant "vigilantism" into its tactics as the movement developed.
He noted that it had also seized on the global Black Lives Matter protests in 2020 to "shift back to more biologically racist themes" of activism.
Extremism experts have noted that the EDL has ceased operating but that the loose networks it forged more than a decade ago are still active and proliferating.
"Modern technology enables individuals to collaborate towards common political goals independent of traditional organisational structures," the Hope Not Hate advocacy group said on Monday.
It noted that most of the recent protests were planned "organically, often by local people, who are plugged into decentralised far-right networks online".
Violence in England over the weekend fitted this mould of more spontaneous demonstrations that caught police off-guard.
'Figureheads'
"These movements lack formal leaders but rather have figureheads, often drawn from a selection of far-right social media 'influencers', in particular Tommy Robinson," Hope Not Hate added.
Robinson -- real name Stephen Yaxley-Lennon -- is a notorious anti-Muslim agitator with a string of criminal convictions who helped found the EDL in 2009.
He has held mass rallies in recent months but is reportedly currently abroad -- although he has maintained a stream of social media posts about the disorder.
His previously-banned X profile was reinstated by the platform's owner, Elon Musk, last year.
Musk himself has been accused of irresponsibly stoking tensions.
On Sunday he posted that "civil war is inevitable" in response to another user blaming the riots on "the effects of mass migration and open borders".
Comerford said platforms like X have been used to "catalyse a huge amount of online anger particularly directed at Muslim communities and migrants based on false information".
"No amount of fact-checking or correction was likely to be able to bring down the heat on some of these protests," he added.
He said that the "speed of mobilisation" by the "amorphous" far-right networks had been "relatively unprecedented".