Tory leadership contender Rory Stewart has hit out at rival candidates, accusing them of racking up a series of “reckless” tax and spending pledges they would be unable to keep.

The International Development Secretary, who launches his campaign on Tuesday, said the “eye-watering” cost of his rivals’ promises risked undermining the party’s reputation for economic prudence.

According to figures released by Mr Stewart’s campaign team, Dominic Raab is the biggest spender so far with £38.2 billion of tax cuts promised.

They include raising the national insurance threshold to £12,500, scrapping stamp duty on homes under £500,000, and a 5p cut in the basic rate of income tax.

He was followed by Michael Gove, whose promise to scrap VAT and replace it with a lower and simpler sales tax was put at £20 billion.

Boris Johnson’s plan to raise the 40% tax threshold from £50,000 to £80,000 was said to cost £14.1 billion, Jeremy Hunt’s promise to cut corporation tax to 12.5% was put at £11 billion, and Sajid Javid’s suggestion he could scrap the top rate of tax was put at £700,000.

In all, Mr Stewart said their commitments added up to £84 billion.

“We must restore – for Britain and for the Conservative Party – our reputation for economic and fiscal prudence. We simply cannot make spending and tax cut promises that we can’t keep,” he said.

“This number – of total spending promises by other candidates in this campaign – is eye-watering. We have to be straight with people, truthful on Brexit, and truthful on spending.

“We cannot criticise Jeremy Corbyn for reckless spending pledges if we start doing the same ourselves. Cheap electoral bribes could cost us dear. Our members are smarter than this.”

Mr Stewart said he would use the fiscal “headroom” from a “good” Brexit deal to invest in education and infrastructure, while borrowing to fund marketable assets such as houses as part of a drive to build two million new homes.

Gavin Cordon is Press Association Whitehall Editor.