Riots across a number of towns and cities have erupted following the murder of three girls at a Taylor Swift-themed event in Southport, a seaside town in northwest England, after false messaging on social media wrongly identified the suspected killer as an Islamist migrant.
Unrest has spread, with rioters targeting mosques and smashing windows of hotels housing asylum-seekers from Africa and the Middle East, chanting "get them out", in the first widespread outbreak of violence in Britain for 13 years.
Keir Starmer has assured English communities they will be safe. (AP PHOTO)
Messages online said immigration centres and law firms aiding migrants would be targeted on Wednesday, prompting anti-fascist groups to say they would counter any demonstration.
Speaking after an emergency meeting with ministers and police chiefs on Tuesday, Starmer said police would be in place to cope with any further disorder.
"Our first duty is to ensure our communities are safe," he told broadcasters.
"They will be safe. We are doing everything we can to ensure that where a police response is needed, it is in place, where support is needed for particular places, that is in place."
He said the fact that protests were being held in multiple locations made it difficult, but he had received the assurance he needed that police could cope with any disorder.
The government has increased prison capacity to cope with the large number of arrests made during the riots, which have prompted a growing number of countries to warn their citizens about the dangers of travelling in Britain.
Starmer said more than 400 people had been arrested, 100 had been charged, and he was expecting sentencing to start soon.
"Anybody involving themselves in this disorder is going to feel the full force of the law," he said.
Three people will be sentenced on Wednesday in Liverpool, northwest England, after pleading guilty to violent disorder, the Crown Prosecution Service said.
The prime minister says anybody involved in riots will feel the full force of the law. (AP PHOTO)
The justice department, which is due to release some prisoners early as it battles a jail overcrowding crisis, said nearly 600 prison places had been secured to accommodate those engaged in violence.
The unrest has prompted India, Australia, Nigeria and other countries to warn their citizens to stay vigilant.
Saminata Bangura, a 52-year-old support worker in a care home in Liverpool said she had felt so welcome in Britain after she moved from Sierra Leone. But she was now scared and largely staying at home.
"I'm so scared, even when I'm walking now, because everywhere, we're scared, especially, we Blacks," she said, describing how a library was vandalised near where she lives.
Starmer has vowed a reckoning for those who have engaged in rioting, hurling bricks at the police and counter protesters, and looting shops and burning cars.
Police on Tuesday charged a 28-year-old man with stirring up racial hatred over Facebook posts linked to the disorder. A 14-year-old pleaded guilty to violent disorder.
On Monday night, trouble flared in Plymouth, southern England, and again in Belfast in Northern Ireland, where hundreds of rioters threw petrol bombs and heavy masonry at officers and set a police vehicle on fire.
