Donald Trump’s budget director has faced fire from Democrats as he attempted to defend the President’s budget proposal – which would slash federal spending on social safety-net programmes by more than $1 trillion (£77.2bn) over the next 10 years.

During a House of Representatives budget committee hearing, Democrats slammed Mr Trump's budget as “cruel” and “immoral”, while most Republicans praised the President’s efforts to curb federal spending.

The President wants legislators to cut at least $610bn (£471bn) from Medicaid – a healthcare programme for the poor – and more than $192bn (£148bn) from the Supplemental Nutrition Assistance Program (Snap), the modern version of food stamps – as well as several other initiatives.

Testifying before the House’s budget committee, Budget Director Mick Mulvaney defended the cuts as ways to reduce the government's debt and balance the budget.

Democratic Representative Pramilla Jayapal of Washington said that that cuts to food stamps, payments to the disabled, and other programmes are “astonishing and frankly immoral”.

Asking about the suggested cuts to Snap, Democratic congresswoman Barbara Lee – who called the proposal “morally bankrupt”, said: “How do you think people are going to survive? Most people on Snap don’t rely on this for a lifetime. It’s a bridge over troubled waters.”

Mr Mulvaney responded by pointing out that there were 47 million people on Snap at the height of the recession, and now there’s 42 to 44 million. There were 28 million beneficiaries of the programme before the recession, he said.

“It’s not unreasonable to ask if there are folks on Snap who should not be, because we should have seen that number go down,” Mr Mulvaney said. “Snap should be counter-cyclical – it should go up during bad economic times and down during better economic times.”

Ms Lee replied: “At least 20 per cent of people eligible for Snap don’t even receive Snap because of stigma and other reasons – so there are more people who need Snap benefits.”

“What about the standard of living for my grandchildren who aren’t here yet, who will end up inheriting $30 trillion in debt, $50 trillion in debt, $100 trillion in debt...What about them?” Mr Mulvaney countered. “Who’s going to pay the bill on this?...Because right now my unborn grandchildren are paying for it, and I think that is morally bankrupt.”

Democratic Representative Salud Carbaja asked the budget director how a 30 per cent cut to the Environmental Protection Agency, as Mr Trump suggests, would affect future generations. However, the congressman's five-minute time allotment for questions ran out before Mr Mulvaney could answer.

Mr Mulvaney's appearance was one of four on Wednesday as Trump Cabinet officials fanned out on Capitol Hill to defend Mr Trump's budget. Treasury Secretary Steven Mnuchin, Education Secretary Betsy DeVos, and Agriculture Secretary Sonny Perdue were also testifying.

The plan, Mr Trump's first as president, combines $4.1 trillion (£3.1 trillion) for the upcoming 2018 fiscal year with a promise to bring the budget back into balance in 10 years, relying on aggressive spending cuts, and a surge in economic growth.

Mr Trump's budget is simply a proposal. There is little appetite among Republicans for a genuine effort to balance the budget – Republican legislators are instead pressing to rewrite the tax code and forge a spending deal with Democrats that would permit higher military spending and restore Mr Trump proposals to cut domestic agencies and foreign aid.

Mr Trump's balanced-budget goal depends not only on 3 per cent growth projections – which most economists view as overly optimistic – but also a variety of accounting gimmicks, including an almost $600bn (£463bn) peace dividend from winding down overseas military operations. The President’s budget also assumes that an overhaul of the tax code would spark the economic growth and generate more than $2 trillion (£1.5 trillion) in higher revenues.

Many – including some in Mr Trump's own party – remain unconvinced. Representative Mark Sanford, a Republican, told Mr Mulvaney that Mr Trump's budget “presumes a Goldilocks economy” that never goes into recession.