Spiralling debt is preventing developing countries from being able to fund vital health services and is instead keeping them trapped in poverty, Christian Aid has warned.
Christian Aid said the UK Government was complicit in the debt crisis as it has direct responsibility for many of the loans given to developing countries under English law or by British-based banks.
It is calling upon the UK Government to change the law to make lending transparent and to stop vulture funds profiting from the debt crisis faced by the world's poorest countries.
Although many international debts were cleared at the start of the 2000s, the situation changed after the financial crisis that hit western countries, including the UK in 2008.
Christian Aid said that the financial crisis had triggered a "boom in irresponsible lending" to countries in the Global South, creating a trap of costly debt repayments that are diverting money away from essential services.
The aid agency's concerns are laid out in a report published on Wednesday, The New Global Debt Crisis, which warns that the debt repayments are exacerbating an already desperate situation.
The report, published in collaboration with the Jubilee Debt Campaign, highlights the case of Sierra Leone, which was forced to take out loans from the International Monetary Fund to combat the outbreak of Ebola in 2014.
It took two years to bring the outbreak under control, during which time the country lost 4,000 people to the disease, including 10 per cent of its health workers.
It warns that large debt repayments are making it harder for the Sierra Leone government to properly fund clinics, health training and even the provision of ambulances.
The lack of adequate healthcare facilities is compounding the dire maternal health situation in the country, where 1,360 mothers die out of every 100,000 live births - the highest death rate in the world.
Christian Aid said the UK had a "moral responsibility" to avert the debt crisis affecting developing countries.
It is also calling upon the Government to write off loans to Sierra Leone.
Laura Taylor, Christian Aid's director of policy and public affairs, said: "It is shocking that developing countries find themselves yet again on the brink of a global debt crisis, 15 years after the last major round of debt relief.
"Countries like Sierra Leone, the most dangerous place in the world to become a mum, face huge debt repayments which deprive them of resources to protect their own citizens.
"It is unacceptable for the UK Government to be complicit in this new debt crisis, which sees some of the poorest countries in the world struggling and unable to get back on their feet following major humanitarian emergencies.
"The UK has a strong history of helping these countries when they are most in need; but too often the lack of transparency in the loans means we are giving with one hand and taking away with the other."