BORIS Johnson's reference to murdered MP Jo Cox in a speech left his colleagues reeling as they accused him of inciting hatred in Parliament.
The first session back quickly descended into a war of words as accusations rebounded off the Commons chamber walls. Here's what we know.
What did Boris Johnson say about Jo Cox?
Boris Johnson referred to Jo Cox in an explosive speech given as Parliament reconvened on September 25, 2019.
The session had been called unexpectedly after Supreme Court judges ruled the Prime Minister had unlawfully suspended Parliament.
In an unrepentant speech, the PM turned on Remainer MPs, using words such as "betrayal" and "surrender" to describe an anti-Brexit bill being passed in early September.
Labour MP Paula Sheriff turned on him, fuming that Mr Johnson "continually used pejorative language to describe an Act of Parliament passed by this House".
Pointing to a plaque in the chamber, commemorating Jo Cox, she 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."
The MP for Dewsbury added: "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."
But firing back, Johnson said: "I have to say, Mr Speaker, I've never heard such humbug in all my life."
Tracey Brabin, who succeeded Mrs Cox as MP for Batley and Spen, said Mr Johnson needed to temper his remarks so that "we will all feel secure when we're going about our jobs".
Mr Johnson replied: “The best way to honour the memory of Jo Cox and indeed the best way to bring this country together would be, I think, to get Brexit done."
What has been said about his speech?
MPs across the house called on Johnson to apologise for his choice of words.
Labour boss Jeremy Corbyn blasted the PM's language and said it "was indistinguishable from the far right", while Lib Dem leader Jo Swinson said Mr Johnson's comments were "a disgrace".
Mrs Cox's widower, Brendan Cox, said he felt "a bit sick" at the way her name was being used and appealed for both sides to calm down.
But he later commented: “I’m sure on reflection, it’s something that he would probably wish he hadn’t said.
"I think it was sloppy language and the wrong thing to say, but I don’t think that he is an evil man.
He said “we should remember our common humanity" and "all of us on all sides of the political debate should take a deep breath and step back from this descent into polarisation”.
The PM's sister, Rachel Johnson, once an MEP candidate for Change UK - The Independent Group, has slammed his comments.
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She told Sky News: "My brother is using words like 'surrender' and 'capitulation' as if the people standing in the way of the blessed will of the people, as defined by the 17.4 million votes in 2016, should be hung, drawn, quartered, tarred, and feathered.
"I think that is highly reprehensible."
In a somewhat evasive statement, Commons leader Jacob Rees-Mogg said all people "had a responsibility to be mild in our language when we're speaking in this House or outside".
He added: "I'm afraid to say it's something where all sides err from time to time and it'd be invidious to pick on individual examples but we have a responsibility of leadership."
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