Unicef will have its UK funding cut by around 60%, the United Nations agency said as it warned the world’s most vulnerable children will “suffer the consequences” of the Government’s move.

The UN children’s fund said on Saturday it was “deeply concerned” by the decision as it urged ministers to restore overseas aid funding by the end of the year at the latest.

It is the latest cut to emerge from the Government’s decision to break its manifesto commitment to maintain spending at 0.7% of national income by slashing it to 0.5%.

Facing widespread criticism, Boris Johnson this week insisted spending would increase when it is “fiscally prudent to do so” as he said the coronavirus pandemic means it is necessary to “economise”.

Unicef urged the Prime Minister to reinstate the 0.7% commitment by the end of the year “at the latest” as it revealed funding for the agency this year would reduce to £16 million, down from £40 million.

“Any cuts to these funds will have serious consequences for children,” the agency said in a statement.

“It is too soon to know the full impact that this and future UK funding cuts will have on Unicef programmes. However, we worry that children living in some of the world’s worst crises and conflicts will suffer the consequences.”

Other funding cuts to have trickled out include an 85% reduction to the UN sexual and reproductive health agency, which it branded “devastating” for women, girls and their families around the world.

A leaked memo has suggested that the UK will slash bilateral funding for overseas water, sanitation and hygiene projects by more than 80% – a move WaterAid described as “savage”.

And a report by media outlet Devex said ministers are planning to reduce funding for polio eradication by 95%.

A Foreign Office spokesman said: “The seismic impact of the pandemic on the UK economy has forced us to take tough but necessary decisions, including temporarily reducing the overall amount we spend on aid.

“We will still spend more than £10 billion this year to fight poverty, tackle climate change and improve global health.

“We are working with suppliers and partners on what this means for individual programmes.”