Protesters wearing Guy Fawkes masks are marching in London in support of organizers Anonymous, who have gathered every November 5 since 2012 to oppose corruption, censorship, inequality and war.
Last year's march in London escalated into disorder as fireworks were thrown at police. Four officers and six police horses were reported to have been injured.
Ahead of this years event, the Metropolitan Police issued set conditions for all who were planning to attend the march:
Almost 20,000 people indicated on a dedicated Facebook page that they were planning to attend the London protest.
The organizers on one of the Facebook pages issued a statement saying that "the police are not your friends." They asked the Metropolitan Police "to restrain from violence and their usual mob mentality."