Sir Keir Starmer has refused to rule out freezing income tax thresholds when asked about the upcoming Budget.
The Prime Minister dodged questions about the Chancellor’s plans from Tory leader Kemi Badenoch in the Commons on Wednesday.
Rachel Reeves is understood to be planning a series of tax raids in her statement on November 26 in a bid to plug a budget black hole of up to £39billion.
Speaking during Prime Minister's Questions, Ms Badenoch said: "This is the first Budget to unravel before it's even been delivered. The Chancellor's cluelessness, I'm afraid, is damaging the economy now.
"The Prime Minister needs to end this shambles. So, can he confirm today that he won't break another promise by freezing income tax thresholds?"
Sir Keir replied: "The Budget is one week today and we will lay out our plans. I've said what we will do in terms of protecting the NHS and public services.
"What we won't do is inflict austerity on the country as they did. What we won't do is inflict a borrowing spree like Liz Truss did."
The current freeze in tax thresholds was brought in by the previous Conservative government after the pandemic and is due to expire in 2028.
But it has been reported that Chancellor Rachel Reeves is likely to freeze income tax thresholds for another two years beyond 2028, in a move to raise about £8billion for Treasury coffers.
Other revenue raises are said to include a “mansion tax” that would hit London and the wider South East hardest.
After her screeching U-turn on plans to break Labour’s flagship manifesto pledge on tax, in order to raise income tax, the Chancellor has been speaking to Labour MPs amid disquiet on the backbenches.
Ms Badenoch slammed the Government over Budget leaks. She added it was "quite clear" Ms Reeves will freeze income tax thresholds.
The Conservative leader told the Commons: "It is quite clear that they are going to freeze thresholds. We didn't get a clear answer from them but this is really important, because in her budget speech last year, the Chancellor said, and I quote, 'I am keeping every single promise on tax that I made in our manifesto'.
"So, there will be no extension of the freeze in income tax and national insurance thresholds. Why was freezing thresholds a breach of the manifesto last year but it isn't this year?"
Conservative MPs laughed as Prime Minister Sir Keir Starmer replied: "Every week she comes along and speculates and distorts."
Sir Keir later added: "[The Conservatives] opposed NHS investment and what did we get? Five million extra appointments in the first year of a Labour Government.
"They tried growing the economy with millions on NHS waiting lists, with our schools crumbling and holes in our roof. It didn't work. "What do they want to do now? Go back to the same failed experiment."
Ms Badenoch earlier asked why the Government had floated income tax rate increases only to U-turn.
She said: "Can the Prime Minister tell us why his Government is the first Government in history to float increasing income tax rates only to then U-turn on it all after the actual Budget?"
Sir Keir said the Budget was next week and that inflation was down.
