Anti-Brexit protesters flooded into central London by the hundreds of thousands on Saturday, demanding that Britain's Conservative-led government hold a new referendum on whether Britain should leave the European Union.
The People's Vote March snaked from Park Lane and other locations to converge on the UK Parliament, where the fate of Brexit will be decided in the coming weeks.
Marchers carried European Union flags and signs praising the longstanding ties between Britain and continental Europe. The protest drew people from across Britain who are determined to force Prime Minister Theresa May's government to alter its march toward Brexit.
Liberal Democrat leader Vince Cable, invited to help lead the march, called the crowd impressive and unified. "There is a huge turnout of people here from all walks of life, of all ages and from all over the country," he tweeted. "We are a Remain country now with 60 per cent wanting to stop the Brexit mess."
Police did not provide a crowd estimate. Independent legislator Chuka Umunna and others supporting a second Brexit referendum estimated the crowd at 1 million.
More than 4m people endorsed an electronic petition this week in favour of revoking Article 50, the act that formally triggered the Brexit process.
The march comes as May, who opposes a second referendum on Britain's EU membership, is easing away from plans to hold a third vote on her troubled Brexit withdrawal plan, which has been strongly rejected twice by Parliament.