The Conservatives have said Kemi Badenoch will not apologise for her language after a fiery Prime Minister’s Questions in which she repeatedly attacked government ministers.

During the Commons session, Badenoch said Labour MPs were cheering on Sir Keir Starmer despite there being “400 knives stuck in his back”, with Speaker Sir Lindsay Hoyle calling for a “little bit more decorum and respect”.

The Conservative leader also suggested many Labour MPs are “traitors and deserters” before branding Education Secretary Bridget Phillipson a “spiteful class warrior”.

Badenoch and Phillipson had a heated exchange in the moments after PMQs, and have since exchanged barbs on social media.

In the first Prime Minister’s Question session since Sir Keir Starmer announced his resignation, Badenoch said Labour MPs have “abandoned” him for a “pair of eyelashes and a black t-shirt” – a reference to leadership frontrunner Andy Burnham.

Sir Keir quit as Labour leader on Monday, paving the way for a new prime minister to replace him as early as next month.

Burnham, the new MP for Makerfield, is seen as the overwhelming favourite for the position.

Badenoch also accused Chancellor Rachel Reeves of “killing jobs” and Energy Secretary Ed Miliband of “killing industry”.

Sir Lindsay intervened to highlight the need to “think about the language” being used in the Commons, saying “when we leave this chamber, don’t be surprised when constituents feel they can use the same language”.

Asked if she would be apologising, a spokesman for Badenoch said “absolutely not”.

It’s not clear what specific language led to Sir Lindsay’s intervention.

A Conservative source claimed the Speaker was unhappy when Badenoch said Labour MPs “don’t like it up them”, a reference to the sitcom Dad’s Army.

But a Labour source claimed the Speaker’s comments related to Badenoch’s criticism of Phillipson.

The pair exchanged words in the division lobbies afterwards, with a Labour source claiming that Badenoch told Phillipson: “You are spiteful, I’m never going to stop talking about how spiteful you are.”

Phillipson is said to have replied: “The public are going to find out who you really are.”

A Conservative source said Badenoch also told Phillipson: “I will fight you all the way, you’re destroying children’s lives” – but that has subsequently been denied by a source close to Phillipson.

Posting on social media, Phillipson later said “Kemi lost her head at PMQs – and afterwards too” and claimed the Conservative leader had previously compared her “to a Gestapo officer”.

She added: “I wonder what it is about a working class woman driving record investment in state schools by ending private schools’ tax breaks that the Tories hate so much.”

Badenoch continued the row by replying that “‘I grew up on a council estate’ is not an excuse for failure”.

She said on X: “You are sacrificing the future of generations of kids on the altar of your class envy – reversing even Labour’s academy reforms.”

Badenoch also wrote: “I speak for those people whose lives you’re destroying and I’ll NEVER stop speaking up for them.”

Earlier in the Commons, Sir Keir defended Phillipson and her “incredible story of social mobility and success” after growing up in poverty.

He said: “She knows that for poor children education is absolutely vital and that is why it drives every single priority and value that she has.”

Badenoch replied: “The fact is if she knew so much about poor children she wouldn’t have given them fewer teachers.”

The prime minister also staunchly defended other ministers, including Reeves, who he said “ended austerity” and had delivered the “right economic plan” to help “weather the global storms”, including the Iran conflict.

Sir Keir said he believes he will hand over the country in “better shape” than he found it.

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