accused Sir of being "on another planet" when it comes to net zero in a fiery clash. The Tory leader hit out at her opponent over Labour's election manifesto pledge to slash energy bills by £300 a year.

Speaking in the Commons, she said: "Why has the Prime Minister broken his promise to cut energy bills by £300?" Sir Keir said: "The way to bring energy bills down for good is to deliver cheap, clean, home-grown energy."

She then asked: "The Prime Minister has broken another promise. He won't admit it but isn't the truth that he can't cut energy bills because of his net zero policy?"

Sir Keir replied: "Energy bills on fossil fuel have fluctuated massively in the last three years because we are exposed to the international market.

"The only way to get bills down is to go to renewable energy."

Mrs Badenoch then said: "This approach to net zero is irrational, it's doomed to fail. Those aren't my words, they're Tony Blair's.

"But the truth is the Prime Minister is on another planet, his net zero plans mean ever more expensive energy.

"Why is he shutting down the North Sea rather than getting our oil and gas out of the ground and making energy cheaper?"

The Prime Minister insisted that oil and gas "will be part of the mix for many decades to come".