Priti Patel has been accused of launching an assault on Britain’s democratic traditions with a crackdown on protests that would make it a crime to cause “serious annoyance or inconvenience” by taking part in a demonstration.

Amid an atmosphere charged by the police use of force at a vigil for murder victim Sarah Everard on Saturday, the home secretary came under fire in the House of Commons over proposed legislation which Labour say would allow someone convicted of vandalising a statue to be sentenced to a longer jail term than a rapist.

Among MPs raising concerns was ex-prime minister and former home secretary Theresa May, who said that freedom of speech was “an important right in our democracy” and warned of “potential unintended consequences” from provisions in Ms Patel’s Police, Crime, Sentencing and Courts Bill.

As MPs began a two-day debate on the controversial legislation, hundreds of protesters thronged Parliament Square outside demanding freedom of speech and better protection for women.

The shadow home secretary, Nick Thomas-Symonds, told MPs that the scenes from Clapham Common should be a “red warning signal” of the dangers of draconian measures in the bill.

A member of Sisters Uncut, a feminist direct action group involved in the Clapham vigil, said: “The police are institutionally violent against women. Handing them more powers will increase violence against women. This bill must be stopped.”

And race equality and criminal justice organisations wrote to Boris Johnson warning the prime minister that the legislation will further entrench discrimination against black and minority ethnic (Bame) communities.

In a letter to Ms Patel co-ordinated by Liberty and Friends of the Earth, 245 charities, community groups and campaign organisations, ranging from Amnesty International to the Ramblers and the RSPB warned that the “draconian” legislation “represents an attack on some of the most fundamental rights of citizens, in particular those from marginalised communities”.

But a string of Conservative MPs said Labour would show themselves to be soft on crime if they vote on Tuesday against the 300-page document, which was published only six days ago and contains a vast array of unrelated measures, including provisions to double maximum punishments for assaults on emergency workers and to end the release of serious sexual offenders after serving half of their sentence.

Ms Patel told the Commons that the right to protest peacefully was “a cornerstone of democracy and one this government will always defend”.

But she said recent years had seen a “significant change in protest tactics” which required police to be given powers to take “a more proactive approach”.

Citing Extinction Rebellion protesters blocking ambulances on emergency calls and gluing themselves to rush-hour trains, she told MPs: “There is a balance to be struck between the rights of the protester and the rights of individuals to go about their daily lives.”

Mr Thomas-Symonds told the Commons that “deep and profound” lessons need to be learnt from the “distressing” scenes at Clapham, where women taking part in the vigil in the face of appeals to stay home due to the coronavirus pandemic were forced to the ground by police officers and handcuffed.

“The scenes from Saturday should be a red warning signal to this House that rushing through ill-judged, ill-thought out restrictions on the right to protest would be a profound mistake that would have long-lasting consequences and do great damage to our democracy,” he warned.

“The right to protest is one of our proudest democratic traditions. That this government seeks to attack it is to its great shame.

“Our existing laws on protest strike a careful balance between legitimate rights and the need to keep order. What our laws on protest do not do, and should never do, is seek to shield those in power from public criticism and public protest.”

He highlighted provisions which would allow police to impose conditions on protests if they generate noise that might result in “serious disruption” to people or organisations in the vicinity.

And he blasted provisions allowing a maximum 10-year sentence for damaging a statue – twice the jail term received by some rapists.

“No government should ever send out a signal that the safety of a statue carries greater importance in our laws than the safety of women,” he said.

Human rights groups have raised concerns that the law’s wording could allow the home secretary to greatly extend police powers to shut down protests, but allowing her to use secondary legislation to define the kind of “serious disruption to the life of the community” or “serious disruption to the activities of an organisation” which would constitute a breach.

The current version of the bill would also allow police to restrict static assemblies and vigils, rather than just moving demonstrations, as well as protests “carried out by one person in a public place”.

And protestors could be arrested and prosecuted if they breach restrictions which they “knew or ought to have known” were in place, a significant hardening of the current threshold which states a crime is committed if they “knowingly” fail to comply.

This would allow prosecution of individuals who had not heard that conditions were imposed by police, even though officers frequently announce such measures by shouting them over megaphones at noisy demonstrations.

Ms May said the law had to be “proportionate” she said and warned that some of the definitions in tne Bill, including of “noise and nuisance”, looked quite wide.

She also warned Ms Patel against giving more powers to the home secretary saying “future home secretaries may not be so reasonable”.

“I would urge the government to consider carefully the need to walk a fine line between the popular and populist, our freedoms depend on it,” said the former PM.

Yvette Cooper, the Labour MP and chair of the Home Affairs Committee, denounced many of the reforms targeted at protests, urging the government to think again and saying “these powers are too broad”.

Liberty’s interim director Gracie Bradley said the bill would hand police the power to decide when and how people can protest, criminalise the way of life of gypsy and traveller communities and create new stop and search powers that will exacerbate discrimination against people of colour.

“Protest isn’t a gift from the state – it’s our fundamental right and under human rights law, states have an obligation to facilitate protest not suppress it,” she said. 

“Yet this is what this bill seeks to achieve. Not content with all but banning protest during the pandemic, the government is now using this public health crisis as cover to make emergency measures permanent. Its new policing bill is an all-out assault on basic civil liberties.”

The cross-party parliamentary joint committee on human rights announced an inquiry into the legislation, voicing concern that a number of its provisions may interfere with rights to liberty, free expression and free assembly guaranteed by the Human Rights Act.