Russell Brand and Vivienne Westwood have joined thousands of masked anti-capitalist demonstrators who have descended on Westminster for a Bonfire Night protest, bringing chaos to the capital.
Scores of riot police were on stand-by amid threats from campaign group Anonymous that the demonstration would create a blockade throughout London.
Officers were forced to draw their batons as missiles, plastic cones and road signs were launched along the Mall, while fireworks were left off in Trafalgar Square.
The masked demonstrators - some as young as 14 - also kicked and dragged over security railings while chanting 'one solution, revolution', as others daubed graffiti on riot vans.
During the march, protesters also let off fireworks and threw firecrackers at police who were guarding the Victoria Memorial, hurling abuse at them.
The crowd surged through central London, pushing over bins, shouting at bemused shoppers and commuters and hitting cars and people with yellow flexible tubes.
At one point, they surrounded a man driving a new Mercedes car and sprayed the back of it with an aerosol, pushing their tubes at him as he opened windows to remonstrate with them.
The protest, known as the Million Mask March, was one of hundreds organised at the same time in cities around the world.
Demonstrators wearing sinister Guy Fawkes masks - made famous in the film V for Vendetta - descended on Trafalgar Square, waving banners and placards, before marching towards Parliament Square at 6.30pm.
As they milled around the square, they chanted anti-establishment slogans before climbing on to the base of Nelson's Column and letting off fireworks.
They then moved onto Buckingham Palace before hundreds of protesters made their way through central London, going to Piccadilly Circus, Regent Street and Oxford Circus.
They then marched to the BBC's headquarters at Broadcasting House on nearby Portland Place and going along Oxford Street to Hyde Park and Park Lane.
The group said in its manifesto that it fights against mass surveillance, austerity and infringement of human rights.
And it added that they have imposed Section 60AA of the Criminal Justice and Public Order Act 1994 across Westminster between 5pm today and 2am tomorrow, which provides powers to remove masks when police fear a crime will be committed.
Scotland Yard said: 'The Met Police deals with around 4,500 protests and events every year. These can range from a single protester to hundreds of thousands of people walking through the capital's streets.
'Officers work with organisers to ensure that people are able to carry out their right to peaceful protest whilst ensuring Londoners can go about their daily business.'
Last year’s London march saw more than 2,500 protesters take to the streets, in a rally which saw fireworks thrown at Buckingham Palace and a total of 15 arrests.
Rather than communicate directly with local authorities, Anonymous sent a message to the government, and to global world leaders: 'To oppressive governments, we say this: we do not expect our campaign to be completed in a short time frame. However, you will not prevail against the angry masses of the body politic.'
British fashion designer Vivienne Westwood was also spotted at the march in central London