Here is the background to the disorder and what has caused it:
WHY DID THE PROTESTS BEGIN?
On July 29, three girls aged between six and nine were killed during an attack at a Taylor Swift-themed dance event for children in the seaside town of Southport, in northern England.
Eight other children and two adults were hurt.
Police arrested a 17-year-old male and false information circulated on social media that the suspect was an Islamist migrant, which led to violent anti-Muslim protests in Southport the following day and an attempt to attack the town's mosque.
The teenager has since been charged with murder and attempted murder. Police said he was born in Britain and have not treated the attack as terrorism.
WHERE HAVE THERE BEEN RIOTS?
The day after the Southport trouble, several thousand people gathered near Starmer's Downing Street office in central London and more than 100 arrests were made following clashes with police.
There have since been riots in more than 20 places across Britain, from Sunderland in northeast England and Manchester in the northwest, to Plymouth in the southwest and Belfast in Northern Ireland.
Most of the protests have involved a few hundred people targeting migrants or Muslims, with police vehicles set alight and bricks, bottles and other missiles thrown at mosques and police officers. Shops, including Asian-owned businesses, have been vandalised or looted.
In Rotherham, in northern England, a hotel that held migrants was attacked, with windows smashed and a large garbage container set ablaze outside.
Around 400 people have been arrested since the disturbances started, police chiefs say, and more than 120 people have been charged in connection with the riots.
WHO IS BEHIND THE RIOTS?
Prime Minister Keir Starmer has said the violence was the result of "far-right thuggery".
High profile anti-immigration and anti-Muslim activists such as Stephen Yaxley-Lennon, known as Tommy Robinson, have promoted the protests online and have been accused by politicians and the media of peddling misinformation to inflame tensions. Robinson has accused the media of lying about him.
Social media firms have been accused by the government of not doing enough to stop the spread of disinformation, while the Institute of Strategic Dialogue think-tank said the companies' own algorithms had played a significant role in amplifying false messages.
Police said those involved in the clashes were mainly far-right agitators from outside their local communities, but that in some cases they had been joined by people with local grievances or young people seeking to join in the disorder.
There have also been large groups of counter protesters, anti-fascist groups and Asian men gathering in some areas where protests have taken place or were expected.
WHY ARE PEOPLE PROTESTING?
Many of those involved describe themselves as patriots who say that record levels of illegal and legal immigration are undermining British society.
Some far-right activists argue online that immigration has fuelled violence and crime, including assaults on women and girls, and that migrants have been housed and treated favourably by politicians. Rights groups say that is simply not true.
Some on the right also accuse the police of treating "patriotic" protesters more severely than they do people involved in, say, recent pro-Palestine marches or Black Lives Matters demonstrations in 2020.
The government and the police have rejected the characterisation of British policing, with Mark Rowley, the UK's most senior officer, calling it nonsense.
Anti-racist groups say looting of shops and attacks on police and mosques betray the true motive of those behind the violence that has broken out at many of the protests, adding that patriotism was being used as a veneer for extremism.
In a YouGov poll published on Tuesday, three-quarters of respondents said the rioters did not represent the views of Britain as a whole, with 7% saying they supported the violence.
WHAT IS THE UK GOVERNMENT DOING?
To quell the disorder, Starmer has said rioters will face the full force of the law.
Nearly 600 additional prison places are being made available and specialist officers are being drafted in.
A 58-year-old British man was jailed for three years for violent disorder at Liverpool Crown Court on Wednesday in one of the first sentences to be handed down over the rioting.
The government has also vowed to go after not just the rioters, but those who used social media to spread the trouble. One man has been charged with using threatening words or behaviour intending to stir up racial hatred over Facebook posts.
Britain's science minister Peter Kyle has met representatives from TikTok, Meta, Google and X to enforce the message that they had a responsibility for helping to stop incitement and the spread of false information.
