Hundreds of masked Anonymous protesters descended on Buckingham Palace tonight as part of a worldwide march against austerity cuts.
A fire was started just yards from the palace gates as protesters threw glass bottles during clashes with police.
Officers in riot gear tried to shepherd the crowd, which was part of a the pre-arranged Anonymous Million Mask Protest.
Several similar events were carried out in cities in Japan, Australia, and New Zealand, in opposition to austerity cuts, corruption and an increase in state surveillance.
In London, a fire was started near the Victoria Memorial, where at least one man and woman were seen being taken away by officers.
Ceylan Hassan, 24, a university graduate said: "They started shouting move back, move back, but we had nowhere to go. The police started pushing us, screaming 'move back, move back'.
"There was a fire on the right hand side of the monument and people started throwing things.
"We've been here from the start, for about four hours."
Protesters were moved back away from Buckingham Palace as the atmosphere grew tense.
Some of those involved in the march were seen ripping barriers from the side of the road.
Sean Roesner, 21, a self-employed computer programmer, travelled to the protest with his brother and friend from King's Lynn, Norfolk this afternoon.
He said: "We turned up and the protest was at Buckingham Palace. When we arrived people were firing fireworks at the Palace.
"It was funny. I didn't have any but I would have fired some if I had.
"I joined Anonymous because I was arrested under the Computer Misuse Act. I spent eight months on police bail last year and had done nothing wrong.
"We are here to stand up for what we believe in, to make the world a better place."
Mr Roesner said his friend had been among a group of people encircled by the police on The Mall and was waiting for him to be released so they could return home.