Rachel Reeves bids to rally Labour backbenchers ahead of Budget as she insists she will still be Chancellor in two years

The message comes before her speech on Wednesday where taxes are expected to be hiked to fill a black hole in the public finances.

Ms Reeves has responded to critics and described leaks within the Labour party in the run-up to the Budget as "incredibly destabilising." She also hit back at "misogyny" in public life, the Times reports.

In a defiant message to Labour MPs in the Commons, she said: "I'll show the media, I'll show the Tories. I will not let them beat me.

• Will the Budget hit your wallet? - Join us on Wednesday from 12pm on the new LBC App for live coverage and clear analysis on what the Chancellor’s plans really mean for you.

"I'll be there on Wednesday, I'll be there next year and I'll be back the year after that."

Referring to critics, she added: "I don't think even I had recognised the misogyny that still exists in public life."

She acknowledged that MPs were unlikely to welcome all the measures to be announced, which is expected to ­include about £30 billion worth of tax rises, but said they should consider the package as a whole.

Read more: Reeves 'to slash cash ISA allowance by nearly half' as Chancellor prepares to raid savers

Read more: Expansion of free school meals will 'make life a little easier', Starmer says

Ms Reeves said: "A budget involves choices. Choices are things that we do, and also things that we don't do.

"I hope that you like every single measure but you might not. There might be 99 per cent or 95 per cent that you like, but 1 or 5 per cent that you don’t. The budget is a package. It's not a pick and mix."

Ms Reeves also hinted that more money would be found for the NHS and to bring down energy bills.

The scale of the task facing the Chancellor was was laid bare after it emerged the Office for Budget Responsibility downgraded its forecast for 2026 and every other year before the next election due in 2029.

The downgrade, and the subsequent reduction in tax revenues, will force Ms Reeves to hike taxes to balance the books and build a bigger buffer against future shocks than the historically-low level of headroom she has previously given herself.

In her search for extra taxes, she could hit more than 100,000 high-value properties with a levy that applies to those worth more than £2 million and could raise £400-£450 million.

Some 2.4 million properties in the top three council tax bands would be revalued to determine which would be subject to the surcharge.

The government will also reveal plans for a tax on milkshakes as part of efforts to make children health­ier and ministers will tell the Commons that they are ending the sugar tax exemption for pre-packaged dairy-based drinks.

Ms Reeves is also expected to scale back projected rises in public spending by as much as £5 billion for 2029-30 as she tries to balance the books, a move economists say is unrealistic.

She is expected to say it is a "Labour budget" with "Labour values" as she commits the government to scrapping the two-child cap on benefits, increasing benefits in line with inflation and ­increasing the national living wage.

Rain Newton-Smith, head of the Confederation of British Industry, warned the Chancellor not to inflict “death by a thousand taxes” on British business.

Speaking at the organisation's conference on Monday, Ms Newton-Smith said: "Prove it – against opposition, against short-term politics, be it on welfare, be it pension increases, show the markets you mean business.

"Short-term politics leads to a long-term decline, and this country cannot afford another decade of stagnation.

"That means making hard choices for growth now before they get harder, having the courage to take two tough decisions rather than 20 easier ones.

"Raising the headroom to make promises stick, it means one or two broad tax rises, rather than death by a thousand taxes."