WE have become familiar with the image of the bogey family on benefits: a huge clan of eight or more children whose parents are jobless or working the system.

Since the UK only has 2,000 families of that size, and a small fraction of those draw benefits, they are unlikely to be consuming a substantial slice of the welfare budget. But their stories are unavoidable. When in 2013 Mick Philpott, the so-called "scrounger", was found guilty of manslaughter after fire killed six of his seventeen children, he was portrayed by some newspapers and politicians as representative of a benefits culture in which parents milked the system by using their children as "cash cows". The Daily Mail described Philpott as a "vile product of welfare UK". George Osborne talked of the welfare state "subsidising lifestyles like that".

Such twisted propaganda has paved the way for the Conservative Government's budget policy of stopping child tax credits at two children. Have a third child and, come 2017, you're on your own (or at least a little more so). Be that third child and you're a surplus, an extra - something that really shouldn't have happened at all.

Of course, there's a way of framing this benefits cut that makes it seem like good, but brutal, housekeeping. It is, in Iain Duncan Smith's words, about "cutting your cloth" - if children are an asset you can't afford, don't spawn them. But it's impossible to escape the eugenic and Malthusian undercurrents that swirl round the debate. Anti-poor sentiments have existed for a long time, but of late there has been an escalation in the shaming of benefits recipients - a scapegoating not only of the ill and disabled, but of the poor who breed.

The Conservatives are prime exponents of the idea. Back in 1974, the Tory Keith Joseph declared: "A high and rising proportion of children are being born to mothers least fitted to bring children into the world ... They are producing problem children ... The balance of our human stock, is threatened." But there has also been a eugenics of the left. William Beveridge, midwife of the Welfare State, advocated graded family allowance schemes in which the educated professional classes would be encouraged to have more children and poor households discouraged from doing so.

Thankfully, come 2017 when the planned cuts take place, those who already have three or more children, won't find their credits stripped away. But if you transgress the small family ethic thereafter, there will be no credits to cover your surplus child. The only exceptions planned, controversially, are for raped woman who may receive support, but must prove they were raped.

Iain Duncan Smith has said this policy is not really about saving money but about fairness to the taxpayer. And if the small number of families involved mean the policy will have little budgetary impact, that's because this depressingly symbolic tactic has been driven by a reverse politics of envy, by taxpayer cries of "unfair" directed downwards towards the poor rather than upwards towards the very rich. Many of its victims will be among the nation's poorest: the poverty rate for families with three or more children is 22 per cent, compared to 16 per cent for smaller families.

Of course, some environmentalists argue that it's better for the planet for everyone to stop at one or two children. But Osborne and Duncan Smith aren't thinking about carbon footprints or global warming. If they were they might consider taxing the children of the wealthy, who appear set to inherit their parents large carbon shoe-size.

Who breeds and who doesn't still matters to many. The message that children are something you can afford or not, a right of those with the means to fund them, is amplified by the fact that Iain Duncan Smith has four children, while David Cameron has three. The privilege of the rich is not just power but progeny. When they talk, as Duncan Smith has done, of the need to provoke "behavioural change", I can't help thinking of Charles Dickens's Ghost of Christmas Present, who admonished Scrooge, saying: "Oh God! To hear the Insect on the leaf pronouncing on the too much life among his hungry brothers in the dust."

Too much life in the dust is what too many complain of now. There is a palpable disgust in certain corners of the media and politics for the multiplying poor, a belief that when someone on benefits reproduces, they are bringing into the world more spongers and scroungers - as if poverty itself were a kind of heritable condition, rather than something escapable through education and work opportunity. In this world-view, it is not just the poor or jobless that are bogeymen, it is also their offspring. Imagine growing up one of these bogey babies, a third child without credit. Aside from the actual poverty, the exclusion from trips and events that your school peers are experiencing, the lack of food or clothing, there is no doubt that the propaganda would touch you, that you would become aware of the attitudes, the shaming of big families such as yours. And you, doubtless, would think the world unfair.