Organisers behind a "Day of Rage" protest have been accused of hijacking the Grenfell Tower disaster for political purposes.
The demonstration, started by Movement For Justice By Any Means Necessary (MFJ), was billed as a day of action for the victims of the inferno.
Coinciding with the British Queen's Speech, police said 500 people joined the march, which aimed, according to the event page, to "bring down the Government".
Several people appeared to be detained by police as tempers flared in Whitehall near Downing Street with protesters and police squaring off as activists yelled angrily.
One man was restrained as he screamed in the face of an officer and another male protester was pinned to the floor by police.
As he was being carried away he repeatedly shouted he was a "peaceful" protester.
Another skirmish with police resulted in a man being led away in handcuffs.
The suspect was seen shouting at the crowd of protesters and was then taken aside by officers.
It was unclear if he had been involved in the day of action.
Signs bearing messages of anger were peppered throughout the crowd during the march, with one reading: "This rage is justified."
Many banners also carried the slogan "Justice for Grenfell", as those marching chanted: "What do we want? Justice."
On regular occasions the demonstrators sang Jeremy Corbyn's name while calling for Theresa May to resign as they marched towards Downing Street.
The ClementJames Centre, which has been helping those displaced by the fire, shunned the movement as opportunistic.
"We cannot emphasise enough how against this many of the affected residents we've spoken to are and they do not want their grief hijacked for any violent or destructive means," a spokesman said.
Far-left activists, the MFJ describe themselves as a "youth-led rights movement" which fights for "justice, equality and respect", according to its websites.
They have staged a string of anti-Government protests over recent years and in March led an event called "Brexit is Racist".
The crowds chanted "let him go" as a man was led, screaming and resisting, away by police.
He was put into a van as a handful of men demanded his release.
After the stand-off with the officers ended, pockets of the demonstration began arguing between themselves.
One girl claimed she was accused of being from a police CID unit by other activists and was seen walking away as they waved at her.
Other sections of the group could be heard arguing over tactics, with one man saying: "If we inconvenience them they will have to listen to us."
Nearby the main body of the protest remained, listening to speeches.
The chants of "Justice for Grenfell" rippled throughout the crowd as they stood in Parliament Square.