JACK McConnell has become the latest senior politician to condemn the UK Government’s “shameful” move to cut the overseas aid budget next year by £5 billion, accusing it of behaving “like the worst kind of playground bully” by picking on the poor and vulnerable.

The condemnation from the former First Minister follows that of David Cameron, the ex-Prime Minister, Nicola Sturgeon, the First Minister, Ruth Davidson, the former Scottish Conservative leader, and fellow Tory Jeremy Hunt, the former Health Secretary.

The rising opposition to the cut in Britain’s aid budget, particularly on Tory backbenches, is paving the way for a possible Commons defeat for the Government when MPs vote on the issue due in January. Its decision would break a pledge in the Conservatives’ election manifesto.

Speaking in the House of Lords, Lord McConnell of Glenscorrodale expressed disappointment at the resignation of Baroness Sugg, the “excellent” Foreign Office Minister, who left her Government role following the announcement to cut overseas aid from 0.7 per cent a year to 0.5%. She branded the decision “fundamentally wrong”.

The Labour peer told the Upper House: “In 2005, I felt an enormous sense of pride at Gleneagles in Scotland as the UK used our leadership of the G8 summit to bring the world together, to unite the world and ensure that there were increased and accelerated commitments from G8 leaders and others to help those living in extreme poverty.

“Is it not shameful that in 2021, the Government will use the months ahead of the G7 summit in the UK to do the exact opposite and, like the worst kind of playground bully, after a year in which a pandemic has reminded us of the interdependence of our world, to pick on the most vulnerable and break a promise to the poor?”

Responding for the Government, Lord True, the Cabinet Office Minister, also paid tribute to his “good friend” Lady Sugg and said: “The Government is committed to supporting international development and helping the world’s poorest people.”

He pointed out that, despite the Government’s decision, the UK would remain the second highest donor in the G7, contributing more than France, Italy, Japan, Canada and the US.

Scottish peer Lord Bruce of Bennachie also paid tribute to Lady Sugg for her “honourable decision” to resign and argued the cut was “unconscionable and mean-spirited”.

The former Deputy Liberal Democrat leader said: “It is all the more shameful because the Government fought two elections in quick succession committed to 0.7%.”

Lord Ahmad, the Foreign Office Minister, said the Lady Sugg would be “sorely missed” by the department, and of the reduction added: “It is a difficult decision but necessary based on the challenges we face.

“However, that said, in real terms this will mean we will still spend £10 billion to fight poverty and climate change amongst other key priorities in overseas development.”

He stressed: “It is temporary and we will return to the 0.7% when the fiscal situation so allows.”

In the Commons, Dominic Raab denied the UK Government was “salami slicing” all parts of the UK’s overseas aid spending as he outlined the priorities for the aid budget.

The row looks set to reach a climax when MPs have to vote on the Government’s proposal.

The Foreign Secretary told MPs the long-term strategic aims of the country’s international work would be based on “our values and grounded in the British national interests”.

The top five areas were tackling climate change, Covid-19, girls’ education, conflict resolution and expanding in-house management of aid delivery “in order to increase the impact that our policy interventions have on the ground”.

Earlier, Rishi Sunak used a round of broadcast interviews to claim Britain was not turning its back on the world’s poorest people.

The Chancellor admitted it was a “difficult decision” to slash the budget but said the UK was in the midst of an “economic emergency”.

Making a statement to the Commons, Mr Raab also expressed “regret” at the decision but said it was necessary as “every penny of public spending will rightly come under intense scrutiny”.

His Conservative colleague, Andrew Mitchell, the former International Development Secretary said his party did “not need to break” its 0.7% spending promise, adding it will “drive a horse and cart” through many of the Government’s aid plans.

He added: “It will withdraw access to family planning and contraception for more than seven million women, with all the misery that that will entail, 100,000 children will die from preventable diseases, two million - mainly children - will suffer much more steeply as a result of these changes from malnutrition and starvation.”

Mr Mitchell welcomed commitments to girls’ education but noted: “On existing plans, probably a million girls will not be able to go to school. I hope he will bear in mind these reductions make little difference to us in the United Kingdom but they make a massive difference to them.”

Mr Raab replied: “With respect, I don’t think it’s possible to say with the precision he did about the implications because we’re not going to take a salami-slicing approach of just saying we’ll cut a third from all areas of ODA[Official Development Assistance].

“We’re going to take a strategic approach, we’ll safeguard those areas that we regard as an absolute priority – including many of the things he mentioned, particularly on international public health alongside Covid, climate change and girls’ education.”

Fellow Tory and Father of the House Sir Peter Bottomley said it would be “illuminating” to see Mr Raab’s messages to the Treasury and Boris Johnson arguing against the cut, noting: “We know it’s not his idea.”

Theo Clarke, Conservative MP for Stafford, added she was “deeply concerned” by the aid cuts.

Her Tory colleague, Devon MP Anthony Mangnall added: “I am horrified that we have decided to break a manifesto commitment and I am horrified at the message that this sends to the many women who have suffered such horrendous acts of sexual violence and conflict, especially given the fact that yesterday was the UN day for an international elimination for the violence against women.”

The overseas aid policy was one of a number of measures outlined in the Spending Review intended to help cope with the economy contracting by an expected 11.3% this year.