International targets to reduce child poverty are going to be missed because globalised trade and cuts to aid budgets are creating an ever-greater chasm between the richest and poorest countries.
More than one billion young people in the developing world are now living in conditions of severe deprivation, according to a report for the United Nations Children's Fund (Unicef). Tens of millions of children in developing countries still do not have access to basic human needs such as food, water and sanitation, the study found.
The report is the first attempt to scientifically measure world poverty, and paints a grim picture of how little the lives of the world's poorest people have improved in the last few years.
A UN declaration in 2000 pledged that by 2015, it would halve the proportion of people whose income was less than one dollar a day and achieve a similar reduction in the number of people suffering from hunger. The declaration also pledged to cut the death rate among the under-fives by two thirds and ensure that all children could complete primary school.
Shailen Nandy, a co-author of the report, said: "At this rate, the goals are unlikely to be met, given declining international commitment to development aid. The results of cutting public spending on basic social services have been an increase in poverty and inequality, a fact which organisations like the World Bank need to acknowledge."
Campaigners warned that globalisation, and pressure on developing countries to liberalise trade, were adding to poverty.
Judith Melby, spokeswoman for the charity Christian Aid, said: "In many countries, poverty is increasing rather than decreasing, particularly in relation to things like malnutrition among the under-fives.
"We have to look at how globalisation has affected these countries. There is a real link between that and poverty levels. They are put under enormous pressure to liberalise their markets, then they lose their indigenous trade to subsidised markets in the EU and the US; and the poorest people, such as subsistence farmers, are left with absolutely nothing."
The report was prepared for Unicef by the Townsend Centre for International Poverty Research at the University of Bristol.
It is the first time child poverty in the developing world has been scientifically measured. The lives of more than 1.2 million children from 46 of the world's poorest countries were analysed for the study.
The report defines children who lack one basic human need, such as food, safe drinking water, sanitation facilities, health, shelter and education are defined as living in severe deprivation, while those without two basic needs are said to be in absolute poverty.
The report found that more than half of all children living in the developing world are living in severe deprivation, while 674 million are in absolute poverty. A third of all children in the survey lived in a dwelling with more than five people to a room, or with only a mud floor.
A similar proportion had no kind of toilet facility and one in five had no access to safe drinking water. More than one in ten children aged seven to eighteen had never been to school, and one in seven was severely malnourished.
Ms Melby said: "We need to make sure that money is carefully targeted and gets to the people who need it most, such as women and children. Health and education are the most important factors, and are closely linked to globalisation.
"If these countries lose income from their own markets, they cut social services and people are forced to pay for health and education. This has a huge impact on the future health and prospects for children."
Countries in sub-Saharan Africa have the highest rates of deprivation, according to the report. In some countries, 90 per cent of children in rural areas were assessed as living in absolute poverty.
Professor Dave Gordon from the University of Bristol and another of the report's authors, said: "Many of the children surveyed who were living in absolute poverty will have died or had their health profoundly damaged by the time this report is published, as a direct consequence of their appalling living conditions.
"Many others will have had their development so severely impaired that they will be unable to escape from a lifetime of grinding poverty. The UN targets were quite modest anyway and yet we are still not going to hit them.
"The Romans managed to provide sanitation for people thousands of years ago, and yet millions of people today still do not have access to a toilet."