As many as 670,000 people gathered in London to call for a second Brexit referendum, according to the People’s Vote campaign that organized the protest. The police said that, in spite of the size, the event passed without any arrests or criminal disruption. If the numbers are correct, it will go down as one of the largest protests ever held in the UK.
The “Stop the War” protest against the Iraq War, held on Feb. 15, 2003, would count as the largest, with at least 750,000 people, according to police figures. The next biggest, before today, was the Sep. 23, 2002 “Liberty and Livelihood” protest, with 400,000 people (it aimed to raise awareness of rural issues).
You can read more about why people were marching in London today in this Quartz story.