Protesters threw missiles, ignited fireworks outside Parliament and set fire to a police car at the million mask march in central London on Thursday night.
Police said that protesters had abandoned an agreed route and timetable for the demonstration.
Thousands of riot police and mounted officers were deployed to contain crowds after the largely peaceful protest at Trafalgar Square and Parliament Square dispersed across the centre of the capital.
To chants of “Tory scum” and “Red solution, revolution”, thousands of anti-capitalist protesters flowed past the capital's landmarks in a cat-and-mouse game with the police amid reports that at least one protester was hit by a car.
The protest - part of a worldwide day of action organised by the Anonymous Hackers' collective - saw protesters don Guy Fawkes masks in an effort to recreate the final scene of the cult film V for Vendetta.
Several protesters were treated for minor injuries and a small crowd was briefly “kettled” by police at Great George Street, a short distance from Conservative Party headquarters.
Most protesters dispersed towards the Palace of Westminster where flares and fireworks were set off and a small drone was flown into Portcullis House, where many MPs have their offices.
Some protesters complained that the demonstration, which had no official leaders and was arranged on Facebook, was poorly organised.
A mixture of banners were on display, ranging from allegations of a political cover-up of child abuse to freedom for Palestine and a more general anti-austerity messages.
Kieran Wyatt, 20, a pest control worker who had travelled from North Wales to take part in the protest, said: “We are all here for different causes, but I'm here because of homelessness. David Cameron wants to help 20 000 refugees but I think we need to look after our own first.”
Others tried to distance themselves from the violent minority. “We are here to show we are not afraid of being involved in democracy any more,” said Dylan Connelly, a shop worker from Stoke-on-Trent.
“There will be violence tonight, but that's not me. I'm here to peacefully show I'm against austerity.”
As the main protest broke up splinter groups headed for Horse Guards, Buckingham Palace, Regent's Street and Leicester Square, where they ended up outside the UK premiere of the latest instalment of The Hunger Games.
“This is so badly organised,” said one balaclava-wearing demonstrator, who did not give his name.
“There's not enough of us.”
The Independent
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