The Bank of England’s 4% inflation forecast is double the target rate of 2% and 0.3 percentage points higher than the prediction made in May.

The figures have raised concerns that living standards could falter amid weaker pay growth and a rise in the cost of the weekly shop, the outlet reported.

This week, the National Institute of Economic and Social Research warned Ms Reeves will likely have to raise taxes as part of “substantial” action needed at the Autumn budget to plug a £51 billion black hole in the public finances.

The fiscal watchdog, the Office for Budget Responsibility, expects the amount the Government spends on pensions to rise to £182 billion by the end of the 2029-30 financial year, up from £142 billion.

Laith Khalaf from the wealth manager AJ Bell told The Times: “No doubt this will once again raise questions about the fairness of the triple lock, especially against a fiscal backdrop which suggests the Chancellor is going to have to stick a shovel into taxpayers’ pockets again in the autumn budget.”

Former pensions minister, Sir Steve Webb, added the triple lock commitment — which Labour promised to maintain during its general election campaign — was an additional pressure on the Chancellor.

He said: “This commitment was not only in the Labour manifesto but has also been used repeatedly to defend the changes to winter fuel payments, so seems unlikely to be broken.

“The challenge for all parties is how to move from the current process to something less generous, not least at a time when the state pension is still not especially generous by international standards.”

On Thursday, the Bank of England slashed interest rates to their lowest level in more than two years, from 4.45% to 4%.

The rate is good news for first-time buyers because mortgage offers could dip, and those on base-rate tracker mortgages will see their rates drop.