The Brexit debate has descended into a “bear pit of polarisation” the husband of the murdered MP Jo Cox has said.
Brendan Cox also said Boris Johnson was “sloppy” in saying the best way to honour the late MP was to get “Brexit done”, but he was not “an evil man”.
The PM had angered many MPs by using words such as “surrender” and “betray” as he addressed the Commons.
A Labour MP referred to her colleague’s murder as she criticised the PM’s remarks after Parliament resumed.
Paula Sheriff referred to Ms Cox – who was killed by a right-wing extremist days before the EU referendum in 2016 – saying MPs faced death threats from people using similar language.
But the PM dismissed her intervention as “humbug”.
Conservative Party Chairman James Cleverly said the debate over Brexit in the House of Commons “generates a huge amount of temper on both sides of the Commons”.
“The best thing we can do to calm things down is to get it delivered, get it resolved,” he added.
Mr Cleverly also said the accusations levelled at the prime minister were “deeply unfair” adding he had never described people as “traitors”.
The highly charged debate – described by the BBC’s political editor Laura Kuenssberg as one of the most brutal she had ever witnessed – came a day after the Supreme Court ruled Mr Johnson’s suspension of Parliament unlawful.
Mr Johnson was forced to cut short his visit to a UN summit in New York to return to the Commons after the UK’s highest court ruled against the decision.
The prime minister insisted to the Commons that the court had been “wrong to pronounce on a political question at a time of great national controversy”.
He also challenged the opposition parties to table a vote of no confidence or back a general election and face a “day of reckoning” with voters.
MPs will later discuss whether to approve a three-day break for the Commons next week while the Conservatives stage their annual party conference.
BBC political correspondent Nick Eardley said opposition parties would also be meeting to discuss their tactics for next week.
During an ill-tempered debate, the prime minister was repeatedly challenged by opposition MPs over his use of the word “surrender” to describe legislation passed earlier this month which aims to block a no-deal Brexit on 31 October if he failed to come up with a new exit deal before 19 October.
Pointing to a plaque in the chamber commemorating Ms Cox, Ms Sherriff said: “We should not resort to using offensive, dangerous or inflammatory language for legislation that we do not like, and we stand here under the shield of our departed friend with many of us in this place subject to death threats and abuse every single day.
“They often quote his words ‘Surrender Act’, ‘betrayal’, ‘traitor’ and I for one am sick of it.
“We must moderate our language, and it has to come from the prime minister first.”
In response, Mr Johnson said: “I have to say, Mr Speaker, I’ve never heard such humbug in all my life.”
Tracy Brabin, who was elected as MP for Batley and Spen after Ms Cox’s murder, also urged the prime minister to moderate his language “so that we will all feel secure when we’re going about our jobs”.
Mr Johnson replied that the best way to honour the memory of Jo Cox – who campaigned for Remain – and bring the country together was “to get Brexit done”.
Mr Cox later tweeted he felt “sick at Jo’s name being used in this way”.
Speaking to Radio 4’s Today programme Mr Cox said “bad behaviour” was not limited to one side of the debate and said words such as “coup” and fascism” are also “inflammatory”.
“This is something which has infected our politics and it’s this vicious cycle where language gets more extreme, response gets more extreme, it all gets hyped up,” he said.
“And the reason that it matters is because it has real world consequences.”
Asked about the use of words such as “coup”, shadow home secretary Diane Abbott told Today that politicians “have been rude about each other since the days of Disraeli and Gladstone” referring to two Victorian prime ministers.
“We all have to consider our language,” she said, but argued that Labour leader Jeremy Corbyn has never used violent language.
“I’m not sure that we can look the nation in the eye and say that was a good day.”
That’s how a Conservative MP has described the torrid scenes in the Commons in the last 24 hours.
Outrage is a common currency these days, but MPs’ jaws dropped as Mr Johnson ramped up the rhetoric in responses to questions – suggesting first that it was “humbug” for a Labour MP to demand he temper his language, to try to protect MPs’ safety.
Then, he went on to say that the appropriate legacy for the MP who was murdered during the referendum, Jo Cox, was for MPs to complete the Brexit process.
No surprise that Labour MPs howled in protest, some left the Commons in disbelief.
And there may be few Tory MPs willing, as the day goes on, to defend how far he went.
Labour leader Jeremy Corbyn said the PM’s language “was indistinguishable from the far right”, while his Liberal Democrats counterpart Jo Swinson said Mr Johnson’s comments were “a disgrace”.
She also told MPs that earlier on Wednesday she reported a threat against her child to the police.
There was criticism from current and former colleagues for Mr Johnson too. Former cabinet minister Amber Rudd – who quit the government and the Conservative Party over Mr Johnson’s approach to Brexit – told ITV’s Peston programme the prime minister’s comments were “dishonest and dangerous”.
And the Conservative former cabinet minister Stephen Crabb told BBC Newsnight that he was “shocked by the way [the PM] responded to the remarks about Jo Cox”.
Culture Secretary Nicky Morgan tweeted that Mr Johnson was “aware and sympathetic” to the threats MPs have received.
“But at a time of strong feelings we all need to remind ourselves of the effect of everything we say on those watching us,” she said.