BORIS Johnson would be guilty of a “grotesquely inhumane” act if he goes ahead with cuts to the UK’s foreign aid budget, the SNP have warned ahead of a Commons showdown today.

Westminster leader Ian Blackford said there would be “devastating consequences” if the Prime Minister insisted on the £4billion cut this year.

It coincided with hundreds of academics and charities, including Oxfam and ActionAidUK, warning the cuts would batter the UK’s credibility at this week’s G7meeting in Cornwall.

They said families would go hungry and girls miss out on an education if the Tories abandoned their 2019 general election manifesto pledge to spend 0.7 per cent of GDP on international aid.

Mr Johnson’s government said last year that it would cut spending to 0.5% of GDP, arguing any more was hard to justify amid record peacetime borrowing due to the pandemic, and said the UK would still spend more than £10bn on aid.

However critics suspect the move was largely political and designed to pander to the Tory right and new Tory voters in former Labour seats.

The Government has said it wants the cut to be temporary, but has refused to give a timetable for it to be restored.

The row has come to a head as more than 30 rebel Tory MPs, including former PM Theresa May and former International Development Secretary Andrew Mitchell, hope to amend a Commons Bill creating a new science agency to frustrate the cut.

They want speaker Sir Lindsay Hoyle to accept an amendment which would force the UK Government to restore the aid level to 0.7%.

If the Speaker agrees, around 45 rebels would be needed for the amendment to pass today.

If the Government looks set for defeat, Mr Johnson could climb down, or offer a compromise, such as a strict one-year cut to the spending.

Mr Blackford said: “The decision to slash the UK’s aid budget amid a global pandemic is grotesquely inhumane and should be condemned in the strongest possible manner.

“Families and communities across the world are facing financial challenges not witnessed in our lifetime, yet this UK Tory government are insistent on implementing more toxic austerity measures which will have devastating consequences.

“It speaks volumes that Boris Johnson would priorities cuts like this during the same period the UK prepare to host the G7. It is truly shameful.

“The harsh reality of this decision is that this will cost lives. The UK have a legal and moral obligation to support countries that are less fortunate than we are – this decision breaks both of those.

“I am urging the Prime Minister to heed the warnings and urgently reverse the UK government’s decision to cut the aid budget. As we continue to battle this deadly virus, we simply cannot abandon those in desperate need of our support.”

In a letter to Mr Johnson, 1,700 charities, academics and business leaders said there was “no justifiable economic need” to break a promise to the world’s most marginalised people.

They said: “The UK’s decision to cut its aid commitment during a pandemic casts a shadow over its ability to deliver at this year’s critical G7 summit.

“While other G7 countries have stepped up their aid budget, the UK is the only one to have rowed back on its commitments.”

They said the cuts meant “nutrition centres and health clinics forced to close, water and sanitation projects cancelled, and 78,000 healthcare professionals left untrained.

“As a result, families are going hungry, girls are not going to school, women’s rights are being sidelined, persons with disabilities are being further left behind, vaccines are expiring on shelves, and diseases are being allowed to spread, and we are reneging on our commitment to lead from the front on tackling climate-change.”

Tom Tugendhat, chair of the Foreign Affairs Committee, said his fellow Tory rebels were “cautiously optimistic”.

He told Sky News: “We’re trying to make sure that Britain’s foreign footprint, that global Britain, really means something. I think that’s absolutely vital to making sure we achieve our ambitions and our potential.

“Britain has a huge opportunity to shape the world at the moment of extraordinary flux and this, along with our defence and diplomatic and trade capabilities, is part of that.

“So I’m absolutely committed to making sure Britain really is great on the international stage.

“The Prime Minister has been as clear as you can possibly be about global Britain being an ambition for all of us, so I’m delighted that he has expressed support and I hope very much that he’ll see that this is an opportunity to demonstrate it.”

Live Aid founder Bob Geldof said the temporary cut in foreign aid “doesn’t make any sense”.

The long-time activist told BBC1’s Andrew Marr Show: “I’m very much afraid that something that we’re told is temporary will become permanent.

“That would be vastly damaging for Britain’s soft power, for its reputation, particularly at a weekend when we invite the world’s most powerful leaders of the world’s biggest economies to come here and talk about such matters with us. It seems remarkably maladroit and inept.”

However UK health secretary Matt Hancock told the same show it was a "temporary" reduction, which was "entirely reasonable" given that the pandemic had caused a "once-in-300-year economic interruption".