Parliament descended into chaos on Wednesday night as tensions flared over a vote on whether to call for a ceasefire in Gaza and the exact language to use.

The speaker of the lower house, Lindsay Hoyle, said he broke with usual parliamentary procedure for the vote because of what he described as "absolutely frightening" threats against lawmakers.

"In parliament this week, a dangerous signal was sent that intimidation works," Sunak said in a post on X.

"It is toxic for our society and our politics and is an affront to the liberties and values we hold dear here in Britain. Our democracy cannot and must not bend to the threat of violence and intimidation or fall into polarised camps who hate each other."

On Saturday, Sunak's Conservatives suspended one of their lawmakers and former party vice chairman, Lee Anderson, after he refused to apologise for saying the London mayor was under the control of Islamists.

Hundreds of pro-Palestinian protesters had gathered outside parliament on Wednesday, with messages beamed onto the building's Elizabeth Tower including "From the river to the sea, Palestine will be free", a slogan critics interpret as a call for the elimination of Israel.

Sunak said Britain had seen an emerging pattern of events which "should not be tolerated".

"Legitimate protests hijacked by extremists to promote and glorify terrorism, elected representatives verbally threatened and physically, violently targeted, and antisemitic tropes beamed onto our own parliament building," he said.

"The explosion in prejudice and antisemitism since the Hamas terrorist attacks on the 7th October are as unacceptable as they are un-British."

Earlier this month lawmaker Mike Freer, who represents an area in London with a large Jewish population, said he would be giving up his parliamentary seat at the next election due to having received threats and after an arson attack on his office.

The Sunday Times and Sunday Telegraph newspapers both reported that several members of parliament have been given taxpayer-funded bodyguards after being assessed to be at risk.

Conservative lawmaker David Amess was killed in 2021 by a man who said he was acting in revenge for the lawmaker's support for air strikes on Syria.

(Reporting by Kylie MacLellan; Editing by Hugh Lawson)