Incredible aerial footage has shown the impressive scale of the People's Vote march through London.
Organisers had estimated some 100,00 would attend.
But some 670,000 descended on the capital this afternoon, it was claimed.
The People's Vote march set off from Park Lane and ended in a rally at Parliament Square.
Footage showed London's streets filled with people from across Britain joined as thousands crowds to call for a second referendum on the final Brexit deal.
People's Vote protesters march on Parliament Square - in Pictures
Celebrity cook Delia Smith, Dragons' Den businesswoman Deborah Meaden and London Mayor Sadiq Khan were among the speakers at the event, which was compered by broadcasters Richard Bacon and Mariella Frostrup.
Sadiq Khan, the Mayor of London, speaking ahead of his platform appearance, said: "Today will go down as an historic moment in our democracy. A moment when in their thousands, people from every corner of our country and every section of our society will take to the streets - coming to make our voice heard.
"We've heard some complain that a public vote would be undemocratic and unpatriotic. But the opposite is true. There's nothing more democratic - nothing more British - than trusting the people to have the final say on our future.
"The lies, the mistruths and the deceptions of the referendum campaign have now been exposed, and it's clear the will of the people is changing. No one voted to leave the EU to make themselves poorer.
"No one voted to make life harder for our children and grandchildren. No one voted to see our NHS damaged. And no one voted for the shambles that this Government has created."
The march was led by a group of young voters calling for a second referendum.
