Rachel Reeves could be gearing up for a £30 billion borrowing bonanza by overhauling fiscal rules.

The Chancellor gave a strong hint she wanted to change the guidelines to encourage more investments.

She said: “It is time the Treasury moved on from just counting the costs of investment in our economy to recognising the benefits too.”

Ms Reeves has committed to meeting the Tories‘ provision that public sector net debt should be falling in the fifth year of a forecast period.

But the Treasury’s losses on the Bank of England’s quantitative easing programme could be excluded from debt calculations.

And new bodies such as Great British Energy could be kept off the books, under rumoured options.

Officials could also be ordered to put more emphasis on the long-term returns from borrowing to invest in infrastructure.

At a later business event, she said: “There are difficult decisions coming in the budget, but what I can promise is we will always give value for money for taxpayers. And we will look at the value and benefits of investment and not just the costs.”