More than 100,000 people are expected to descend on central London to march in support of a second referendum on leaving the EU.
Organisers are hoping the protest, calling for a final say on the Brexit deal, will be the “biggest, loudest and most important”.
The aim of the march and campaign is to demand ‘a democratic voice to be heard on Brexit’.
Grassroots campaign group People’s Vote UK, said: “This Government has failed on Brexit: there is no mandate for its car crash proposal or for a disastrous no-deal Brexit.
“We won’t let them get away with a bad deal - that’s why we will be there in Central London making the case for a People’s Vote.”
The march will be led by young people who feel their voices “were ignored” during the first referendum, the group said.
“A crisis is coming this Autumn when MPs will have to decide whether to make our country poorer, trash our vital public services and wreck the life chances of the young or give us all a People’s Vote on any Brexit deal.”
Several MPs and celebrities have confirmed they will be attending including Alan Partridge star Steve Coogan, TV chef Delia Smith, actor and comedian Dawn French, Tory MP Anna Soubry, Green Party’s Caroline Lucas and The Mayor of London Sadiq Khan.
Many people intending to join the march shared pictures of the banners they had made on social media.
The protestors will gather at midday on Park Lane before marching to Trafalgar Square and then heading to Parliament Square, where the protesters will hear speeches.