Boris Johnson has avoided a damaging Commons defeat after Tory rebels were denied a vote on the prime minister’s planned cuts to overseas aid.

The government has slashed its spending of 0.7% of national income on aid, a legal target and 2019 Tory manifesto pledge, to 0.5%.

It triggered a backlash from a significant number of Tory MPs including ex-PM Theresa May and former cabinet ministers Andrew Mitchell and David Davis.

The rebels were hoping to use an amendment to legislation setting up the Advanced Research and Invention Agency to force the new body to make up the funding to meet the 0.7% goal from next year.

A vote would have taken place on Monday evening and rebel ringleader Mitchell said the amendment was likely to pass with a majority of between nine and 20.

But Commons Speaker Lindsay Hoyle ruled that the amendment was too far outside the scope of the purpose of the bill, so there will be no vote.

However, Hoyle urged the government to bring forward an “effective” vote on the issue, meaning Johnson could in future face a damaging defeat at the hands of the rebels and be forced to reverse the cut.

Responding to the Speaker’s decision, Mitchell said the government was treating MPs with “disrespect”, potentially acting unlawfully by ignoring 2015 legislation enshrining the 0.7% target, and “indisputably” enacting a cut which would lead to the deaths of hundreds of thousands of people around the world.

Sources told HuffPost UK that the rebels could now try and force an emergency debate on the cut on Tuesday, which would have no impact on policy but could prove embarrassing for Johnson as he prepares hosts leaders from some of the world’s richest countries at the G7 summit in Cornwall this weekend.

The rebels are also unlikely to be allowed to reintroduce the amendment via the House of Lords, but one MP stressed: “The movement [for 0.7%] will continue.”

Mitchell, a former international development secretary, said maintaining the 0.7% figure would have meant Johnson could have met G7 counterparts on Friday as “first among equals”.

Responding to Hoyle’s decision, he told the Commons: “In the week of the British chairmanship of the G7, the government’s failure to address this issue will indisputably mean that hundreds of thousands of avoidable deaths will result.

“It is already attracting criticism from all round the other members of the G7.”

He also accused the government of “riding roughshod over parliament” and “seeking to thwart our democratic rights as members of the House of Commons”.

Davis, a former Brexit secretary, told BBC Radio 4’s Today that the “harmful” and “devastating” cuts would result in deaths around the world.

There will be massive cuts in efforts to provide clean water, which will kill children worldwide, and in funding for food for starving people, where “again thousands will die”, he said.

“No other G7 country is cutting its aid in this way. It is going to have devastating consequences across the world. Historically, I am a critic of aid spending, but doing it this way is really so harmful.”

Shadow international development secretary Preet Kaur Gill said: “The strength and depth of support for protecting the aid we send to help the world’s poorest is clear.

“The Conservative government is leaving the UK isolated among wealthy countries by being the only one to cut this budget.

“A failure to reverse the cuts would entirely undermine our ability to solve global challenges, from the pandemic to the climate crisis.

“Rather than trying to evade another vote, the government must end its retreat and reaffirm its commitment to spending 0.7% of national income with a clear timeline.”

Some 1,700 charities, academics and business leaders jointly have written to the prime minister to warn that the UK’s “credibility and voice on the international stage will be undermined” just as he prepares to preside over the G7 gathering, which will include his first face-to-face meeting with US president Joe Biden.

The letter, with signatories including Oxfam GB and Save The Children, said the aid cuts are a “double blow” to the world’s poorest communities in the midst of a pandemic.