Sir Keir Starmer has refused to rule out more tax rises or spending cuts next month despite saying “big decisions” have already been taken.

Rachel Reeves is said to be considering imposing a “stealth tax rise” as she grapples with ways to plug the fiscal black hole ahead of the Spring Statement.

The Chancellor is reportedly searching for tax increases to patch up economic forecasts and flattening growth – making it more challenging for her to abide by her own fiscal rules.

One of the options Ms Reeves may consider is extending the income tax freeze following 2028-9, pushing thousands into higher tax bands as a result of increasing wages.

Following last year’s £40billion tax-raiding Budget, the Chancellor assured taxpayers that she would not “come back with more tax increases”.

But with the economy continuing to flounder and both borrowing and inflation soaring she needs to find money from somewhere.

Ms Reeves is now preparing her team to draft up her Spring Statement on March 26.

Asked whether he was happy for the Chancellor to raise taxes or make spending cuts next month, Sir Keir declined to rule anything in or out.

Speaking to reporters en route to Washington, he said: “Well, we are at the early stages of that, and obviously I am not going to get ahead of myself until we have made decisions.

“But as I have said before, in terms of the big decisions on tax obviously the Budget was the place that we took those decisions – but as ever, going into a statement I am not going to say in advance what we might do and what we might not do.

“But let me not let hares running, the big decisions were in the Budget of last year and that’s the way we are approaching this spring statement.”

It is understood that Ms Reeves intends to focus on minimising public spending if necessary.

One insider told the Financial Times that she was taking “nothing off the table”.

The Institute for Fiscal Studies (IFS) think tank has announced that freezing income tax thresholds beyond 2028-9 could rake in £4billion each year, if National Insurance brackets were frozen.

IFS chief Paul Johnson announced that making such moves would be “relatively politically painless” and that Ms Reeves could always unfreeze the threshold at a later date if the economy improves.

The freeze would not require further legislation in the Commons but could be considered a positive for the public finances later on by the Office for Budget Responsibility.

Mr Johnson said: “I’m surprised the Chancellor didn’t extend the freeze in the Budget – it would have given them a bit more headroom against their targets.”