Oliver Dowden said Angela Rayner and Keir Starmer are the "Phil and Holly" of British politics in a fiery PMQs exchange.
In his first stint standing in for Rishi Sunak, the Deputy PM made a cringe comparison to the This Morning presenters, who are claimed to be all smiles on the surface but fighting behind the scenes.
Deputy Labour Leader Ms Rayner told the Commons: "It's absolutely amazing that while the Labour Party is preparing to govern with a Labour majority, his party has started to prepare for opposition."
She listed controversial comments made by Tory MPs the National Conservative Conference this week as she accused ministers of not knowing what was going on in their own party.
Ms Rayner told Mr Dowden: "The right honourable gentleman sitting opposite, while working in Number 10, said he had to listen to the radio every morning to find out what was really going on in the country.
"Apparently, he was surprised on a daily basis by what he learned and most of his time was spent on day-to-day crisis management. Eleven years on, nothing has changed."
Mr Dowden replied: "I'm not quite sure what the question was. But if she wants to talk about this or this sort of thing. We all know what's going on with her and her Leader. It's all lovey dovey on the surface, they turn it on for the cameras, but as soon as they're off, it's a different story.
"They're at each other's throats. They are the Phil and Holly of British politics."
Mr Dowden was promoted to Deputy PM after Dominic Raab was forced to resign last month after a bullying investigation upheld claims against him.
Ms Rayner told the Commons: "It's a pleasure to welcome yet another Deputy Prime Minister to the despatch box. The third deputy that I face in three years, and you know what they say? The third time's a charm. And I'm also pleased to note that the Prime Minister has a working class friend, finally.
"I seem to remember that after the loss of 300 Conservative seats at last year's local elections, he (Oliver Dowden) resigned, saying someone must take responsibility. After a thousand more Conservative councillors have been given the boot by voters, who does he think it is responsible now?"
Ms Rayner's jab about the PM having a "working class friend" comes after Rishi Sunak was last week admitted people say "silly things" as a "teenager" in a bizarre defence of a clip showing him saying he has no working class friends.
The Deputy Prime Minister replied: "In the spirit of her opening remarks, can I just say, it really is a pleasure to see her here today. I was, though, expecting to face the Labour Leader's choice for the next Deputy Prime Minister if they win the election. So I'm surprised that the Lib Dem leader isn't taking questions today.
"You will forgive me if I take her predictions with a pinch of salt. After all, she confidently predicted that the right honourable member for Islington North (Jeremy Corbyn) would one day be prime minister."
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