Rachel Reeves failed to rule out further tax rises in the autumn as new figures showed the economy shrank more than expected in April.
The Chancellor has repeatedly said the cost of Wednesdayâs spending review is covered by the tax rises she brought in last year, saying departments must now âlive within their meansâ.
But economists have warned a weakening economy and additional commitments such as reversing much of the cut to winter fuel payments mean taxes are likely to go up again in the autumn.
Asked on Thursday whether she could guarantee there would be no further tax rises, Ms Reeves told LBC: âI think it would be very risky for a Chancellor to try and write future budgets in a world as uncertain as ours.â
But she again repeated her promise that she would not need to increase taxes on the same scale as last year, when she put them up by ÂŁ40 billion.
She rejected the suggestion she was a âKlarna Chancellorâ who had announced a âbuy now, pay laterâ spending review.
She said: âThe idea that yesterday I racked up a bill that Iâm going to need to pay for in the future, thatâs just not right.â
Her comments come as the Office for National Statistics reported the economy shrank by 0.3% in April â the biggest monthly contraction since October 2023 and worse than the 0.1% fall most economists had expected.
In recent days, both Ms Reeves and Number 10 have said the economy is beginning to turn a corner, allowing them to fund the U-turn on the winter fuel allowance.
But Thursdayâs worse-than-expected economic news will make it harder for Ms Reeves to balance her spending commitments with Labourâs promises on tax and borrowing.
Paul Johnson, director of the Institute for Fiscal Studies, said: âMs Reeves is now going to have all her fingers and all her toes crossed, hoping that the OBR will not be downgrading their forecasts in the Autumn.
âWith spending plans set, and âironcladâ fiscal rules being met by gnatâs whisker, any move in the wrong direction will almost certainly spark more tax rises.â
The Chancellor acknowledged the reduction in GDP was âdisappointingâ, and blamed âuncertaintyâ caused by Donald Trumpâs announcement of sweeping tariffs at the start of April for much of the fall.
But opposition parties have laid the blame squarely with the Government, with Conservative shadow chancellor Sir Mel Stride accusing Ms Reeves of âeconomic vandalismâ.
He said: âUnder Labour, we have seen taxes hiked, inflation almost double, unemployment rise, and growth fall. With more taxes coming, things will only get worse and hard-working people will pay the price.â
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