“Hundreds of thousands” of people are expected to take to the streets this weekend in response to the Prime Minister’s plan to prorogue Parliament.
Anti-Brexit campaign group Another Europe Is Possible has organised 32 #StopTheCoup demonstrations to take place on Saturday.
Momentum is also calling on its members to “occupy bridges and blockade roads” in conjunction with the protests.
Disruption is the only form of leverage protesters can rely on
Michael Chessum, national organiser for Another Europe Is Possible, told the PA news agency that “disruption is the only form of leverage protesters can rely on”.
He said the group is not encouraging demonstrators to block roads, but that kind of disruption is “certainly possible”.
He added: “We would go further than anticipate (civil disobedience). We would defend it.”
Labour leader Jeremy Corbyn has urged MPs to join the demonstrations and oppose the shutdown of Parliament.
In a letter to the Parliamentary Labour Party, he said: “I am addressing a major rally in Salford on Monday.
“But there are also public protests across the country this Saturday, there will be a rally in Parliament Square on Tuesday evening, and I encourage Labour MPs to be present and to share our message.”
Labour MP Clive Lewis also called for people to support the #StopTheCoup protests.
The shadow treasury minister said: “The right to peacefully protest and show your displeasure and anger is a long-held British tradition.
“No one is calling for riots or aggravation. This is about people peacefully demonstrating.
“A peaceful protest can be marching, but it can also be sitting down in roads.”
Further mass demonstrations, organised by the People’s Assembly Against Austerity, are planned to take place on Tuesday to coincide with MPs returning to Westminster.
Petition surpasses 1.5 million signatures
The calls for protests come as a petition against Prime Minister Boris Johnson’s plan to suspend Parliament racked up more than 1.5 million signatures as of Friday morning.
It also follows multiple protests in London, Edinburgh and other cities on Wednesday, which took place within hours of Mr Johnson announcing his plans.
Mr Chessum said he expects to see “hundreds of thousands” of people taking part in the demonstrations across the UK on Saturday, with the protest in London being the largest.
He said: “Ultimately we are not going to persuade Boris Johnson to change his mind through some intellectual exercise.
“This process needs to force the Government to change its course.”