"The government will undertake a robust process to assess groups for extremism against the definition, which will then inform decisions around government engagement and funding," said a public notice from Michael Gove, Sunak's secretary of state for leveling up, housing, and communities.
The government is expected to release a list in the coming weeks of groups it deems as in violation of the new definition of extremism.
The U.K.-based human rights group Reprieve warned that "placing the power to define who is and who is not 'extreme' in the hands of a single cabinet minister is a nakedly political gesture which purports to defend liberal democracy but is fundamentally illiberal and undemocratic."
The notice was published amid widespread outcry over the U.K.'s support for Israel's relentless bombardment of Gaza, where the Israel Defense Forces have killed at least 31,341 Palestinians since last October.
Tens of thousands of Britons marched through London over the weekend, demanding that Sunak push Israel to declare an immediate and permanent cease-fire and to condemn the prime minister's recent comments, in which advocates said "support of the Palestinian cause" had been conflated "with extremism."
"I am here to support Palestine, to call for an end to the genocide, and to call out the double standards of our government," one protester, Sundari Anitha, told The Guardian on Saturday. "They are widening the concept of extremism to attack the right of people to protest. I'm here both to defend the rights of Palestinian people and also my freedom to criticize my government."
Sacha Deshmukh, chief executive officer of Amnesty International U.K., noted on Thursday that the government's Prevent program has also been marked by the 2023 Public Order Act, which expanded the definition of a "serious disruption" by protesters and imposed penalties of up to 12 months in prison.
"From the prime minister's disturbing Downing Street speech earlier this month, the introduction of further anti-protest measures, and now the expansion of the extremism definition, it looks as if the government is set on shrinking the space for dissenting views and the right to protest," said Deshmukh. "An overwhelmingly peaceful protest movement seeking an end to Israel's mass killing of civilians in Gaza is being used by ministers to clamp down on our civil liberties—the irony is crushing and frightening."
He continued:
This attempt to stigmatize legitimate, peaceful political activity is taking us further down the road toward authoritarianism.
In any democracy worth the name, nonviolent political activity should be protected and even celebrated as a sign that a country respects human rights and differing opinions.
[...]
The government should recognize that real British values involve defending the rights of all political opponents to speak freely and openly.
Deshmukh said Amnesty has found in its research that "legitimate political activity" is already being referred to the government under the Prevent program.
"If criminality among certain groups or organizations is suspected, we already have a host of laws to deal with this," he said. "Today's announcement is a dangerous gimmick and this whole enterprise should be abandoned."
Other critics of the government's new focus on so-called "extremism" include Peter Hain, a member of the Labour Party and the House of Lords, and Member of Parliament Diane Abbott.
"I think it's an appalling direction to go down and [the definition] could probably have been applied to the suffragettes in their day, who were equally vilified, spat at, hated, and treated very badly by the police and the authorities," Hain told The Guardian on Sunday.
LGBTQ+ rights campaigner Peter Tatchell noted that "British values" in the past have included "slavery, colonialism, homophobic discrimination, and the denial of votes to women and working-class people."
"Broadening the definition of extremism risks criminalizing peaceful protests by legitimate groups," he told The Guardian.
