Police have arrested 53 people in the annual Million Mask March.
Thousands of protesters wearing the trademark Guy Fawkes masks descended on Trafalgar Square in support of the hacking collective Anonymous.
By 9pm, 14 had been arrested on suspicion of drugs offences, 11 for obstruction, three for the possession of an offensive weapon or blade, and two for public order offences.
The anti-capitalism march was limited to a three-hour period between 6pm and 9pm on a prescribed route between Trafalgar Square and Whitehall this year after last year's scenes of violence.
There were angry scenes during the procession, with police forming a ring of steel outside Parliament.
Members of the crowd ignited fireworks and flares in front of Westminster Abbey.
Shortly before 9pm, as the end of the march approached, there were chaotic scenes as riot police moved in to make an arrest.
A group of protesters surrounded and charged the officers, with shouts of "f*** the police" and "police brutality".
Angela Windsor, an unemployed 40-year-old, said she travelled from Wales to take part in the event.
She said: "Nobody is protecting people - nobody cares.
"I think everyone here cares enough about people to make the effort to come down and try and do something, because the officials aren't doing it."