The former Foreign Ministry head warned Rachel Reeves not to cut UK spending on international aid, amid signs that the prime minister is willing to raid the development budget to help pay for higher defence spending.

Simon McDonald, a former foreign ministry civil servant, said that if Reeves chooses to reduce aid, it would damage the UK's global reputation as she seeks to save in this year's spending review.

Government sources told the Guardian that the aid budget is one of many areas of savings, and the Prime Minister asked ministers to justify every commodity the government spends.

But after President Donald Trump recently frozen U.S. aid programs, McDonald's warned that such a move would have a serious impact on the world's poorest people.

He told the Guardian: “Dynamic assistance is an easy target for pruning when economic needs are needed, as international aid is often not a priority for voters.

“I hope the Treasury won’t cut the knife for further cuts: not only has the UK’s international reputation won a huge effort from the cuts in 2020, but with the cuts from the US Agency for International Development, the international demand for this help is more than It's ever been bigger."

He added: "When times are tough, part of the budget that is most vulnerable with voters is the most vulnerable. I think the Foreign Ministry will be able to show its huge impact, but ultimately, if that has nothing to do with taxpayers or voters, then Must be fragile."

A government spokesman called the prospect of cutting the aid budget "pure speculation." They added: "Our development spending is crucial to lifting out of poverty on a world of habitable planet, and the UK remains one of the most important donors in the G7."

Asked if the Prime Minister was considering cutting aid, another official close to the expenditure review process said: "Everything in this expenditure review is at risk."

Reeves faced one of her biggest challenges as prime minister when she announced her three-year spending plan in June.

The budget plan last year will cut unprotected sectors by more than 1% each year from 2025/26 to 2027/28. Since then, however, the cost of borrowing in the UK has risen, leaving the Prime Minister looking for further spending cuts to avoid borrowing exceeding her initial commitments.

Her work has been harder by the government's commitment to increase defense spending to 2.5% of GDP - a commitment the Prime Minister has stressed in recent weeks in response to Trump's negotiations with Russia about Ukraine's future.

In addition to defense, health and education budgets are protected. During the three-year period, other departments were asked to develop plans to cut 5% to 11%.

Officials say one of the most vulnerable sectors is the Ministry of Foreign Affairs, whose budget has actually been cut by more than a third in the past five years.

To find the cuts required by the Treasury Department, Foreign Secretary David Lammy must take into account cuts at home and abroad, as well as the aid budget.

McDonald's said it could prune London's civil servants, but warned against cutting Britain's diplomatic forces.

"The network is crucial to the UK - our eyes, ears and brains are all over the world," he said. "You never know where it might suddenly matter to the UK's interests."

"Running is relatively cheap: cutting 50 positions will save only about £5 million. When I was permanent secretary, the CEO of FTSE told me they were surprised at how low the Ministry of Foreign Affairs' operating expenses were. They paid three for the global network To four times, that gives us a small portion of our coverage.”

But many officials are equally concerned about the aid budget, given the impact of Trump’s decision to freeze his government aid program and cut staff from the country’s aid agencies.

The president's decision has led to overnight HIV services in South Africa, with 5,000 health care professionals in Ethiopia being fired and potentially wasted nearly $500 million in food aid.

Currently, the UK spends about 0.5% on aid for gross national income as former Prime Minister Boris Johnson cuts it from 0.7% in 2021. Labor has promised to restore it to 0.7 per cent "once the fiscal environment allows", but aid experts are now worried it will reduce again.

Bond CEO Romilly Greenhill said on behalf of the Development NGO: “Any advice to cut development and humanitarian spending in the U.S. to fund defense spending is reckless, short-term , it will actually destroy, it will actually destroy Britain's own security interests."