Keir Starmer is facing calls to order an inquiry into social media to prevent platforms turbo-charging future riots in the wake of the appalling scenes in recent days.
Cabinet ministers have warned online posts acted as a “rocket booster” for the organisation of violence, while No 10 clashed with Elon Musk after the billionaire used his X platform to claim “civil war is inevitable” in Britain.
Vital lessons have to be learned to stop social media “fuelling” similar outbreaks in the future, the Liberal Democrats said.
The prime minister has said the police should remain on “high alert” amid fears of more trouble this weekend.
6,000 riot officers are to be deployed to potential hotspots, while almost 600 arrests have now been made in relation to the disorder.
Gavin Stephens, chairman of the National Police Chiefs’ Council, warned those “intent on violence and destruction have not gone away”.
He also suggested police patrols could be stepped up at lower league matches, following concerns of flare-ups at the start of the football season.
Sir Keir also warned those involved online they would face the courts if they break the law as he told social media executives they should be “mindful” of the real-world consequences of the messages they publish.
Ministers would have to “look more broadly at social media” in the wake of the riots, he added.
His warning came as Jordan Parlour, 28, a Facebook user who encouraged people to attack a hotel housing asylum seekers was jailed for 20 months for stirring up racial hatred at Leeds Crown Court On Friday.
“We cannot let this moment go by without a proper inquiry to learn vital lessons and stop social media fuelling appalling violence like this in the future,” Lib Dem cabinet office spokesperson Christine Jardine said.
She said that the “thugs” behind the riots had to face the full force of the law. “But social media giants must also be held to account for their duty to prevent criminal activity on their platforms. They have been too slow to act and proved they can’t be left to their own devices,” she said.
Tim Newburn, professor of Criminology and Social Policy at the LSE, whose Reading the Riots unofficial inquiry into the 2011 riots led to the home secretary announcing a review police stop and search powers, told The Independent: “A failure to consider some kind of official inquiry would be a mistake”.
He added: “We should do it because we should do it because we want to reduce the likelihood of it happening again. If we want to mitigate these problems. We can’t prevent it, but to reduce the chances, then we have to take seriously I think asking those kinds of difficult questions.”
Former top prosecutor Nazir Afzal said he supported an inquiry that would look at the role of social media.
A new YouGov poll shows two-thirds of the public believe social media companies should be held responsible for posts inciting criminal behaviour, while seven in ten, 70 per cent, believe they are not regulated strongly enough.
London mayor Sadiq Khan has also called on ministers to look again at the Online Safety Act, saying the riots show new rules due to come into force are “not fit for purpose”.
It is designed to make platforms take “robust action” against illegal content and activity.
But Mr Khan blamed social media for misinformation spreading “very quickly”.
The Lib Dems want an inquiry to examine the way social media was used to organise riots and incite violence, as well as the impact of conspiracy theories and misinformation spread online.
False claims the alleged attacker of three young girls in Southport was on a watchlist and Muslim were used to stir up far-right mobs.
Mr Musk was also a victim of misinformation on his own platform after he tweeted fake news Sir Keir was considering building detainment camps in the Falklands.
Ms Jardine said: “Our hearts are still broken for the family and friends who lost three young girls, and for the community of Southport, which has gone through so much pain in recent days. Sadly, so much pain was caused by violent gangs who were hell-bent on causing destruction.
“It has been very disturbing to see people in the UK and abroad using social media to organise these riots and incite racist violence on our streets.”
Mr Afzal said it was important to have a short inquiry “to report by the spring next year, so we can plan for any further disorder next summer”. He agreed it should look at the role of social media, as well as other issues, such as the profile of rioters,policing, resilience and preparedness.
No 10 sources pointed to comment by the prime minister on Friday that social media is “not a law free zone”. “And I think that’s clear from the prosecutions and sentencing,” he added.
“That’s a reminder to everyone that whether you’re directly involved or whether you’re remotely involved, you’re culpable, and you will be put before the courts if you’ve broken the law.”