By Andrew MacAskill and Amanda Ferguson
LONDON / BELFAST (Reuters) – Hundreds of thousands of supporters of the European Union marched through London on Saturday in the biggest demonstration the terms of Brexit.
The protesters waved the blue and gold flag of the EU and held up "Bollocks to Brexit" banners under sunny skies to call for another referendum on the eventual deal on Britain wants to leave the world's largest trading bloc.
The Prime Minister Theresa May in Prime Minister Theresa May, in which she failed to agree with EU leaders in Brussels and received her condolences in the talks.
With just over five months until Britain has come to a close, a deal with the EU wants to look like some Rebels in May's Conservative Party.
James McGrory, one of the organizers 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 can not be delivered, "he said.
At the march, demonstrators carried placards saying "Brexit is pants", "Time for an EU turn" and "European and proud."
Organizer said about 670,000 people took part in the march, which would make it the largest in Britain since a demonstration against the Iraq was in 2003.
The "People's Vote" campaign, which includes several pro-EU groups, said they had stewards at regular intervals to estimate the size of the crowd. The police did not provide independent estimate of numbers.
Protesters originally gathered near Hyde Park and then walked past Downing Street and finished outside of Parliament where they listened to politicians from all main political parties.
Britain's 2016 referendum saw 52 percent vote in favor of leaving the European Union. But the past two years have been politically fractured as the government has been struggled to agree on a plan.
Some opinion polls have shown a slight shift in favor of remaining in the European Union, but they have become a decisive change in attitudes and many in Britain increasingly bored by Brexit.
The prime minister has repeatedly ruled out holding a second referendum. The opposition Labor Party's Brexit spokesman said last month's party open to a second referendum with the option of staying in the bloc in certain circumstances.
In Belfast, Northern Ireland, around 2,000 people gathered on Saturday to oppose Brexit.
Brendan Heading, a 39-year-old IT worker, said he was worried the decision to leave the EU would damage the economy and could lead to the break up of the United Kingdom.
"I feel that Brexit threatens prosperity and stability," he said.
Brexit supporters held their own rally in the town of Harrogate in the north of England.
Richard Tice, Vice-Chairman of Leave Means's Leave and One of the Speakers at the event, described the People on the March in London as "losers" and said a second referendum would trigger a constitutional crisis.
"We had a vote, we voted to leave, the idea to have a second referendum would be incredibly damaging," he said.
"People need to be ill as they feel about what is a significant potential for a total betrayal of democracy in this country."
Reporting By Andrew MacAskill; Editing by Ros Russell