Activists are taking to the streets in Kill the Bill protests across the country, calling on the House of Lords to reject the Police, Crime, Sentencing and Courts Bill.
Demonstrations are taking place in cities including London, Bristol, Coventry, Newcastle, Liverpool, Manchester, Sheffield, Plymouth on Saturday.
The action comes ahead of a crucial vote on the bill by peers on Monday.
Demonstrators describe it as a draconian crackdown on the right to assembly, freedom of expression and other civil liberties.
In London, many hundreds marched from Holborn to Parliament Square in Westminster chanting “Kill the bill” and carrying banners reading “Defend the right to protest” and “We will not be silenced”.
Members of a wide range of social, racial and environmental justice groups joined the rally demanding that their peers prevent the law from becoming law.
Ben Hancock, 70, from London, told the PA news agency: “The measures are really completely draconian, basically depriving everyone of the right to protest.”
“I mean, we’re effectively being reduced to a state similar to Russia.”
Sue, a 62-year-old, who asked to use only her first name and had traveled to the protest as part of Extinction Rebellion from Godalming, Surrey, said: “And I think some of the provisions in this bill are going to severely limit things that we can do to protest.”
Tied to another protester, she continued: “So for example we won’t be able to be like that together, hold hands or even tie together.
“There are many, many things we cannot do and protests will really be a thing of the past.
“And so many of the freedoms that we have in this country were won through protest.
“Not just because people are silent about it and those in power decide they’re going to give people freedoms, but because people took to the streets and made noise and protested.
“And I still want to be able to do that, I want my children to be able to do that.”
Terry Matthews, 69, from South London, said: “I think we are facing a really sharp attack on our right to protest and our freedom to show our dissatisfaction with the status of the government and the country.
“And it’s a really dangerous step to make the attempt.”
The bill would subject protesters to long jail terms and hefty fines for acts that cause “serious nuisance,” which noise alone could cause.
It would expand stop and search powers, and new laws against staying ashore with a vehicle would effectively criminalize Gypsy, Roma and Traveler communities.
Amendments added to the bill by the Government in the House of Lords in November would make obstructing major transport work a criminal offense and would give police the power to ban named people from demonstrating.