The number of UK children living in "severe poverty" rose in the four years before the recession, research from a children's charity suggests.
Save the Children says the number of children in homes in this category rose 260,000 to 1.7m from 2004 to 2008.
The report warns there is a danger that severe poverty could rise even further.
The government says it has lifted half a million children out of relative poverty, and helped the very poorest, as defined by its own criteria.
It has pledged to halve child poverty by 2010 from the 1998/99 figure of 3.4 million and end it altogether by 2020.
'Shocking'
Lee Muir, who lives in Motherwell in Scotland with her six-year-old son Kai, told Radio 5 Live: "On a daily basis I've had to make decisions on whether to heat my house or whether to feed my son.
"Extra curriculum activities are just out the window completely, that's just not an option just now."
The government defines relative low-income poverty as less than 60% of contemporary household median income, and absolute low-income poverty as less than 60% of 1998/99 median household income.
However, Save the Children defines severe poverty as those living in households with incomes of less than 50% of the UK median income (disregarding housing costs) and who were also missing some basic possessions, such as a winter coat.
The charity used this method to try to analyse if help was reaching the very poorest families.
We're talking about children going without a winter coat, a bed and other day-to-day essentials
Fergus Drake
Save the Children
Save the Children calculated there were 1.46 million children in what they call severe poverty in
2004-05. Four years later the number had risen to 1.7 million.
The charity claims that at the end of 2008, 13% of the UK's children were living in severe poverty, up two percentage points on 2004 - and that not only have efforts to reduce child poverty stalled, they have gone into reverse.
The report predicts the recession is likely to have increased severe poverty by a further 100,000 children, but that benefit payments and tax credits would have brought numbers back down to pre-recession figures.
Save the Children's director of UK programmes Fergus Drake said: "It's shocking that at a time when the UK was experiencing unprecedented levels of wealth the number of children living in severe poverty - we're talking about children going without a winter coat, a bed and other day-to-day essentials - actually increased."
The story varies across the UK. In Northern Ireland, 8% of children are extremely poor. In Scotland it is 9% while in England and Wales it is 13% - a figure pushed up by the situation in London where 19% of youngsters live in severe poverty.
'More to do'
Work and pensions minister Helen Goodman said: "Families with children in the poorest fifth of the population are, on average, £5,000 better off as a result of personal tax and benefit changes.
"Without measures such as tax credits, employment help and the Sure Start programme, it is likely around 2 million more children would still be in poverty today.
"Significant investment made since the Budget of 2007 will lift a further 550,000 children out of poverty and we are helping to get parents into work by providing free childcare for three and four year olds.
"But there is still much more to do. We are determined to meet our ambitious goals and help break the cycle of deprivation - which is why we will enshrine in law our commitment to end child poverty by 2020."
http://news.bbc.co.uk/1/hi/education/8479364.stm