The BBC's Niall Dickson: The number of homes where no-one has a job has doubled in twenty years

He said a Treasury study found two out of every five children were born poor and three million grew up in low income families.

The survey concludes 12 million people in the UK are living in poverty. A substantial widening of the gap between rich and poor has occurred since 1977.

The study defines those in poverty as people earning less than half average income. As such, a couple with children making less than £150 a week before housing costs (or £129 after) would be termed poor.

Gordon Brown: "The low paid have been taxed too highly"

The Conservatives argue the government is in danger of increasing poverty by removing some benefits aimed at encouraging people to marry.

But Mr Brown insisted his changes in the March Budget would help the poorest in society.

Gordon Brown: Trying to break "poverty trap"

"The people who have lost out most of all in the last 20 years, who do need help, are the low paid who have been taxed too highly," he told BBC Radio 4's Today programme.

"It is not something for nothing we're offering. We're saying, in return for you accepting responsibilities to work or to bring up your children, we will help you.

"We're not going to spend money simply compensating people, as we did in the past, for their poverty. We're genuinely going to tackle the causes of poverty."

Children 'learn to be poor'

The Treasury study comes on the same day as a survey by the Joseph Rowntree Foundation suggests some children from low income families may be "learning to be poor".

The BBC's Niall Dickon analyses the Treasury report into the causes of child poverty

The Rowntree study found youngsters had lower aspirations if they spend their childhood watching their parents without money to buy goods they wanted.

Based on interviews with 400 children, it suggested those living in households claiming income support were five times more likely to think their family income was inadequate than other children.

Children of low-income families often lack career ambitions, the Rowntree study says

Thirty-nine per cent of the children interviewed were from single-parent families. They were four times more likely to believe their family income was inadequate.

Youngsters from single-parent families and families on income support were more likely to discuss money with their parents and siblings.

They were less likely to ask for expensive presents or to receive regular pocket money and had lower career expectations than other children. They were also more likely to choose unskilled or semi-skilled jobs.

The study's author, Sue Middleton, said: "Children from low income families are learning to expect and accept less from an early age and to find ways of covering up the disappointment.

"It seems entirely possible that for some children it is early learning of this sort that reduces both their immediate expectations and their future aspirations.

"There is a real sense in which they are learning to be poor."

Pledge to end child poverty

Earlier this month, Prime Minister Tony Blair promised to wipe out child poverty within 20 years.

Mr Brown is using the publication of the Treasury report, Tackling Poverty and Extending Opportunity, to drive home his message that welfare reform and improved childcare provision is the best way to eradicate poverty.

He stressed his intention was to make work pay for those on low incomes.

"The proper way to build a cohesive society is to help families with children, to help all who work and encourage people to work and, most important of all for the future, to get people the skills to work so that they can earn well and they can have a career.

"We have a very big challenge to meet the prime minister's challenge of abolishing child poverty over the next 25 years.