The UK has cut its funding to the United Nation's Population Fund (UNFPA) by a "devastating" 85 per cent, the agency announced on Thursday.
Britain, traditionally the UNFPA's largest contributor, will donate £23 million this year (€26.5 million) down from an expected commitment of £154 million (€177 million).
The UN agency aims at improving reproductive and maternal health worldwide, providing access to contraceptives, supplies for safe pregnancies and abortions and training for health workers.
It said in a statement that the UK's "retreat from agreed commitments made to the programme in 2020" will be "devastating for women and girls and their families across the world."
"With the now withdrawn £130 million (€149.5 million), the UNFPA Supplies Partnership would have helped prevent around 250,000 maternal and child deaths, 14.6 million unintended pregnancies and 4.3 million unsafe abortions," it added.
In November, the government of British Conservative Prime Minister Boris Johnson prompted an outcry within its own ranks and among charities when it would abandon its target of spending 0.7 per cent of national income on foreign aid, in favour of a 0.5 per cent commitment.
The move was expected to cut foreign aid funding by nearly a third and free up about £4 billion (€4.6 billion). The government argued the cut was necessary due to the "domestic fiscal emergency" triggered by the COVID-19 pandemic.
UNFPA said in its statement that it "recognises the challenging situation facing many donor governments, yet deeply regrets the decision of our longstanding partner and advocate to step away from its commitments at a time when inequalities are deepening and international solidarity is needed more than ever."
"The truth is that when funding stops, women and girls suffer, especially the poor, those living in remote, underserved communities and those living through humanitarian crises," it went on.
A spokesperson for the UK's Foreign, Commonwealth and Development Office (FCDO) told Euronews that "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 (€11.5 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," they added.
According to UNFPA data, the UK contributed $215 million (€177.3 million) to the agency in 2019.
The other donor countries in the top 10 were Sweden (€118 million), Canada (€88.6), Denmark (€75.8), the Netherlands (€73 million), Norway (€70.3 million), Germany (€37.3 million), the European Commission (€35.5 million), Japan (€25.8 million), and Switzerland (€24.8 million).