Thousands of people joined a march in London yesterday to demand a people's vote on Brexit. Photo / Getty
More than half a million anti-Brexit campaigners gathered for a protest dubbed "The People's Vote March" in central London calling for a second referendum.
Organisers, who originally expected around 100,000 expected to attend, said 670,000 demonstrators marched from Park Lane to a rally in Parliament Square.
If true, today's demonstration would be the biggest since 2003 when an estimated one million people protested against the Iraq War in the streets of London.
About 150 buses ferried thousands of activists from across the country to the capital.
Thousands of campaigners arrived dressed in royal blue clothing emblazoned with gold stars, brandishing signs which read "bin Brexit now" and "I want a say on Brexit".
London Mayor Sadiq Khan said yesterday's event was a 'march for the future' for young Britons, including those who were too young to vote in Britain's 2016 EU membership referendum, when those who favor leaving the bloc won by 52 per cent to 48 per cent.
The mayor, from the opposition Labour Party, has previously backed mounting calls for a fresh referendum so that the public can have a say on whether they accept Conservative Party Prime Minister Theresa May's Brexit deal or choose to stay in the EU.
He told the BBC that "what's clear is that the only options on the table now from the prime minister are a bad Brexit deal, or no deal whatsoever. That's a million miles away from what was promised two-and-a-half years ago".
Organisers of the rally, People's Vote UK, posted to Twitter: "Well over HALF A MILLION are marching on Parliament today, demanding a #PeoplesVote on the Brexit deal. Everybody needs to know this."
The protesters were joined by other famous faces including comedian Eddie Izzard, who came dressed in a navy suit waving British and EU flags.
He said: "I can't think of anything more democratic, anything more British, than trusting the judgement of the British people."
Lord Of The Rings actor Andy Serkis attended the rally with his wife and son, and described it as "one of the most, if not the most important march of a generation".
Elsewhere, Crazy Rich Asians and Humans star Gemma Chan tweeted a snap of herself with a banner reading: "Even Baldrick had a f****** plan".
James McGrory, one of the organisers of the march, said voters should have the chance to change their minds because the decision will impact their lives for generations.
"People think the Brexit negotiations are a total mess, they have no faith in the government to deliver the promises that were made, partly because they cannot be delivered," he said.
The People's Vote campaign, which includes several pro-EU groups, said they had stewards stationed at regular intervals to estimate the size of the crowd. The police did not provide an independent estimate of numbers participating.
Northern Ireland voted to remain in the EU by 56 per cent. One placard hoisted aloft in the crowd said: '56% say protect Good Friday.'
People fanned out around a stage in front of the city hall down the main shopping street, Donegall Place, to hear speeches focused on environmental, human rights, business and student concerns.
Residents of border communities who oppose Brexit were also present.
Britons voted to leave the trade bloc by a narrow margin in the 2016 EU membership referendum and Prime Minister Theresa May has ruled out another public vote on the subject.
Britain is scheduled to leave the EU on March 29, but negotiations have been plagued by disagreements, particularly over the issue of the Republic of Ireland-Northern Ireland border, which will be the UK's only land frontier with the EU after Brexit.
There are growing fears of a "no-deal" exit, which could create chaos at the borders and in the economy.
The #PeoplesVoteMarch crashed the internet! Wasn’t able to get signal for hours but snuck into my office. @BBCNews reporting that this as as biggest march though central London since Iraq. We know how that worked out when govt ignored. Theresa May take heed! pic.twitter.com/38aFXWlRbX
May said at an inconclusive EU summit in Brussels this week that she would consider a longer post-Brexit transition period - one that could keep Britain aligned to EU rules and obligations for more than two years after its March departure.
Pro-Brexit politicians in Britain saw it as an attempt to bind the country to the bloc indefinitely.
"This week's fresh chaos and confusion over Brexit negotiations has exposed how even the best deal now available will be a bad one for Britain," said Andrew Adonis, a Labour member of the House of Lords.
"Voters will neither forgive nor forget if (lawmakers) allow this miserable Brexit to proceed without people being given the final say."