The Prime Minister has assured communities they “will be safe” amid fears further far-right disorder is due to break out in London and elsewhere on Wednesday.
Sir Keir Starmer said on Tuesday evening the criminal justice system has shown a “robust and swift response” in the face of ongoing unrest across the country.
Violent disorder has taken place in London and other cities and towns, following a knife attack in Southport that killed three young girls last Monday.
Following an emergency Cobra meeting on Tuesday evening, Sir Keir said he is expecting “substantive sentencing” for those taking part in the unrest “before the end of this week”.
“Those involved will feel the full force of the law…over 400 people now have been arrested, 100 have been charged – some in relation to online activity – and a number of them are already in court,” he said.
“I’m now expecting substantive sentencing before the end of this week.
“That should send a very powerful message to anybody involved, either directly or online, that you are likely to be dealt with within a week.
“Nobody, but nobody, should be involved themselves in this disorder.”
On Tuesday evening, the Met’s deputy assistant commissioner said it is “very clear” that “hateful and divisive groups across the capital” were planning to cause further disruption on Wednesday night. He warned those involved “will face the full force of the law”.
London Mayor Sadiq Khan said that "now is the time to check in on your Black, Brown and minority friends... in many parts of the country, they don't feel safe."
He added: "Our communities are facing the threat of hatred - including violence - fuelled by insidious racism, prejudice, and Islamophobia.
"It’s the legacy of decades of dog whistles, including from some irresponsible politicians."
A nursery in Leytonstone, east London, has asked parents to collect their children early on Wednesday evening to allow time for staff and children to get home safely ahead of the planned disorder.
The Met has vowed to use “every power, tactic and tool available” to clamp down on what it has described as “one of the worst spates of violent disorder in the last decade”.
More than 100 people were arrested in London last week, as police were “attacked” and flares thrown at the Downing Street gates.
In a stark statement released on Tuesday evening, the Met’s deputy assistant commissioner Andy Valentine described the violence as a “national critical incident”.
“This country is faced with one of the worst spates of violent disorder in the last decade,” he said.
“This is a national critical incident and we will do everything in our power to protect London and its communities.
“We know about the events planned by hateful and divisive groups across the capital tomorrow night. They’ve made their intention to cause disruption and division very clear.
“The scenes of racist, thuggish and criminal behaviour across the country have been deeply shocking. Members of the public and officers have been attacked, many have been injured.
“We will not tolerate this on our streets. We will use every power, tactic and tool available to prevent further scenes of disorder. We arrested more than 100 people in central London disorder last week and we will not hesitate to arrest hundreds more if they take to the streets intent on fuelling violence.
“Our message to anyone who plans to breed disorder is clear – you will face the full force of the law.
“Our officers put the safety of others above that of their own. They have faced dangerous and violent scenes and verbal abuse in the name of public service and keeping the King’s peace. They will continue to fulfil their duty in the coming days and weeks.
“Londoners in parts of the capital will see more officers in their local area. If anyone is concerned or needs our help, please speak to them. They are there to help.
“Our officers and our communities have truly pulled together in these difficult times. We are proud to stand together against the vile and criminal behaviour we’ve seen in recent weeks.”
Prime minister Sir Keir Starmer was set to chair an emergency Cobra meeting on Tuesday night, as police across the country braced for an eighth night of violence.
The meeting of the Government’s emergency response committee was to be the second in two days as officers anticipated further disorder.