Let's call him Martin. Martin is small for 11. He rarely eats breakfast. He struggles with reading and number work. His brother is in a gang and his mother is a heroin addict. He lives in the area of Glasgow that boasts the lowest male life expectancy in Britain: 54. His school clothes are grubby and he smells unwashed. He doesn't have a social worker because he's never been in more than minor trouble. Not yet.

This is not the child poverty Thomas Annan's camera recorded in the backcourts of Victorian Glasgow, where thin, ragged, barefoot children played in the dirt, let alone the child poverty of waifs in Addis Ababa scouring rubbish dumps for plastic carrier bags to sell for a pittance. Yet Martin is instantly recognisable as one of the 210,000 children in Scotland living in poverty. This is the reality of relative poverty. Because he is shod and isn't starving and probably lives in a home that has both a telephone and a television, many people would say he "isn't really poor".

In fact, they would probably say "real poverty" no longer exists in Britain. But Martin is poor because he is part of a group that is falling behind what most ordinary people take for granted in his society. Without a lot of help, Martin's chances of leaving school with a respectable set of Standard Grades and getting a decent job are minimal, and his chances of ending up on benefits or in prison are extremely high. This week's Scottish poverty figures provide a window into the bleak lives of boys such as Martin. Ask people about the 20,000 Scottish children who do not have birthday parties or go on school trips, or the 150,000 who go without a week-long summer holiday, let alone the 30,000 whose parents can't afford to heat their homes, and they might change their minds about Martin being poor.

Government politicians so frequently manage to slip into their rhetoric those 600,000 British children who have been hoisted out of poverty on their watch that most of us have stopped listening. We shouldn't because it is probably the government's finest achievement. It follows nearly two decades of being told by the Conservatives that "wealth trickles down from the top", "that a rising economic tide lifts all boats". It doesn't. In fact, so few crumbs fell from the rich man's table over 20 years that by 1996 one-third of British children were below the poverty line, compared with 14% in 1979. If society was a train and the poorest 10% were in the guard's van, it had come uncoupled and was grinding to a halt while the rest sped off towards the sunny uplands of economic prosperity.

When Tony Blair announced to a conference on poverty in 1999: "We should be the first generation to end child poverty forever," many in his audience thought their ears needed syringing. But he went on to pledge that Labour would reduce child poverty (children in households living on less than 60% of median earnings) to zero by 2020.

Thanks to the minimum wage, various welfare to work initiatives and the working families tax credit, the 2005 interim target was met in Scotland and only narrowly missed in Britain. But this week's figures show that Britain's poorest children are slipping behind again. In Scotland, the numbers in poverty appear to have stalled, though given that the total number of under-18s is falling, this is hardly anything to boast about. And though the £1bn announced in last week's Budget to boost tax credits and the £150m to help get parents into work announced yesterday will come in handy, they may only enable Labour to run on the spot. Both the Institute for Fiscal Studies and the Joseph Rowntree Foundation have calculated that billions more need to be spent if the 2010 child poverty target is to be met.

The contention that this is a blip and the insinuation that it has been caused by self-employed parents lying about their incomes are, frankly, shoddy. Having been enticed back into work, many parents, especially those paying childcare costs, are simply not earning enough to pull them out of poverty. Half of all poor children have working parents, but part-time office cleaning and bar work on the minimum wage are not enough to lift them above subsistence.

Benefits and tax credits intended to bridge the gap are so complex and their administration so accident-prone that many do not receive their due. And because they have failed to keep abreast of wages, median earnings have risen but inequalities in society are starting to widen again. Straightforward redistribution may be both crude and politically unacceptable but perhaps it's about time we admitted that child poverty can't be abolished in a society in which the heads of our top 100 companies earn 75 times more than their average employee. The equivalent figure in 1980 was 10.

For Martin and his ilk, there is another problem. To date, government policies have done more to help those most likely to get work but the bottom 5%-10% of workless families face much higher hurdles. Many are second- or third-generation unemployed. Many have literacy and numeracy problems and even more struggle with mental illness, as well as other health problems. Helping them into work isn't only hard but thankless because most of them don't vote.

By contrast, pouring money into the pockets of middle-class families with disabled children or the affluent elderly, are more likely vote-winners. Eradicating child poverty is one of the toughest social pledges ever made by a British politician. To carry it through will require a strong moral commitment on many fronts.

Around 30 years ago, I used to cover Glasgow and Inverclyde housing stories. Fresh from the south of England, it was hard to believe that families lived in homes that had no inside toilets, mushrooms growing on the carpets and more water coming through the roof than out of the taps.

Much political heavy lifting by both district councils and community-based housing associations transformed that situation, but now a new crisis looms in the availability of decent affordable rented housing, as this week's report from Shelter Scotland demonstrates. Children who come out of inadequate homes tend to have poor health and poor prospects, so housing belongs at the top of the political agenda.

Initiatives such as Sure Start Scotland, the Working for Families Fund and Pathways to Work have been extremely successful at getting parents back into the workforce, but an obsession with work as the route out of poverty puts the cart before the horse in households with alcohol, drugs and mental health problems. Too many projects in these areas are underfunded, too thinly spread or shelved before they can make an impact.

Tackling child poverty is not just about money, but how it is spent. To take a single example, why do so few children, such as Martin, have their own social workers? Has the time come for the radical reform of social work in Scotland, focusing attention on specialists capable of turning boys like him into future taxpayers, rather than future claimants or prisoners?

How much do we care about other people's children? That's what it comes down to.