British police have charged a 17-year-old boy with the murder of three young girls and 10 counts of attempted murder in a knife attack at a summer dance class that has shocked the nation and sparked two nights of violent protests, Paralel.Az reports citing Reuters.

The teen, who cannot be named due to his age, will appear at Liverpool Magistrates Court on Thursday over Monday's incident at a "Taylor Swift yoga and dance workshop" summer vacation event for children in the seaside town of Southport.

Large disturbances broke out in the northwest English town on Tuesday after false information was spread on social media that the suspect behind the stabbings was a radical Islamist migrant, with anti-immigrant protesters descending on the town from elsewhere.

In London on Wednesday, thousands gathered near the prime minister's Downing Street residence, shouting "Save our kids", "We want our country back" and "Stop the boats", as well as English football chants. More than 100 people were arrested.

Police have said the attack was not terrorism-related and that the suspect was born in Britain, quashing speculation on his origins.

"Whilst these charges are a significant milestone within this investigation, this remains very much a live investigation," Chief Constable Serena Kennedy told a press conference shortly after midnight.

As well as killing three girls aged six to nine, Monday's attack in the normally quiet town left eight other children with stab wounds. Five remained in critical condition in hospital, along with two adults who tried to protect them, police have said.

More than 50 police officers were hurt in the protests in Southport on Tuesday, when demonstrators set police vans on fire and dismantled garden walls to hurl bricks at officers. In London on Wednesday protesters threw flares and smoke canisters towards Downing Street.