Violent outbreaks have taken place across Britain, including violent unrest in Hartlepool, Manchester, and Aldershot.
Prime Minister Sir Keir Starmer will meet senior police leaders on Thursday to offer them the "full backing" of the government in the face of the unrest.
In central London, a large protest was staged under the title of Enough is Enough, with arrests made after demonstrators clashed with officers in Whitehall on Wednesday July 31.
The Metropolitan Police said: “Last night during a planned protest on Whitehall, police officers were attacked and subjected to assault, abuse and violent disorder.
“111 arrests were made for offences including violent disorder, assaults on police officers, possession of knives and offensive weapons and breach of protest conditions. A dedicated team of officers are currently working to bring charges against those responsible.”
Demonstrators were seen launching beer cans and glass bottles at a line of police in riot gear in front of Downing Street and throwing flares onto the statue of Winston Churchill in Parliament Square.
The angry scenes also included loud chants of “we want our country back” and “Oh Tommy Robinson”, referring to the right-wing activist.
It comes after violence erupted in Southport on Tuesday following a vigil for three girls killed in a knife attack at a Taylor Swift-themed holiday club.
Police officers in Southport suffered serious injuries when bricks, stones and bottles were thrown and cars were set alight during violent protests.
The disorder near the town’s mosque came after false rumours were circulated online about the suspect.
The unrest comes as a 17-year-old Axel Muganwa Rudakubana, was charged with the murders of the three girls.
Alice Dasilva Aguiar, nine, Bebe King, six, and Elsie Dot Stancombe, seven, were fatally stabbed on Monday when a knifeman entered the dance class on Hart Street in Southport, Merseyside.
Eight other children suffered knife wounds – with five of them in critical condition – while two adults were also critically hurt.
1. Police officers detain a protestor during the 'Enough is Enough' demonstration on Whitehall
The protest was held in reaction the Government's response to the fatal stabbings in Southport on July 29. | AFP via Getty Images
2. Police officers detain a protestor
More than 100 people were arrested at the protest in central London | AFP via Getty Images
3. Hundreds of protesters gathered outside Downing Street
Violent outbreaks have taken place across Britain, including violent unrest in Hartlepool, Manchester, and Aldershot. | AFP via Getty Images
4. Protests have swept the county
Demonstrators were seen launching flares towards the gates of Downing Street and at a statue of Winston Churchill. | AFP via Getty Images