Johann Hari: When divorce is the wiser option

Another David Cameron policy has been proved to be based on false right-wing myths in the past month – but who has told you about it? Who knows that his set-piece proposal for fixing Britain has just been shown to make things worse?

You know the script. David Cameron says "the only way to mend Britain's broken society" is to "mend the institution of marriage" by handing £40 a week to married couples. This Married Couple's Allowance would, he says, discourage them from splitting up.

Set aside the question of whether any couple would actually take a £40-a-week bribe to stay together. The logic behind the policy itself is based on a plausible-sounding reading of the facts.

At first glance, the sociological evidence shows that the kids of broken homes or single parents are more likely to drop out of school, slip into crime, and become drug addicts than children whose parents stay together. So the solution is, to Cameron, obvious: keep parents together using the tax code and these problems will slowly be reduced. Stop Jimmy's mum and dad splitting, and Jimmy will be more likely to stay in school, on the right side of the law, and off drugs.

A major study has just shown that this is based on a simple misunderstanding of the evidence. Professor Kelly Musick and Dr Ann Meier of Cornell University have carried out a study of children whose parents stay together for the sake of the kids. We all know some: parents who can't stand each other, but have made a hard-headed decision to stay together nonetheless. They are exactly the kind of people who would be glued back together by Cameron's policies if they succeeded in their goal.

It turns out their children do worse than any other group – including those of divorcees or single mums. If you are raised by arguing parents who stayed together only for you, then you are 33 per cent more likely to become a binge-drinking teen than if you have a single parent, for example. Having parents locked in live-in combat damages children more than having separated parents, or just one single parent – and the damage lasts well into adulthood. The offspring are more likely to have bad marriages themselves, and more likely to have children at a very young age.

It makes sense. Would Jimmy rather have a happy mum and dad who live apart, or depressed, stressed, angry parents sharing a bed?

So Cameron's first glance at the figures turns out, then, to be wrong. He was comparing divorcees and single parents to happy two-parent families who want to stick together. But happy two-parent families who want to stick together are not what his policy would create. If he had an effect at all, he would be tying together miserable couples who would otherwise have split. To assume you would get the same sociological outcomes from them is an Enron-style accounting error.

In fact, this new study shows that Cameron's policy would actually unwittingly harm children. It's not his intention, but we would have more children in the worst-performing category of all, and so in the long term increase the very social dysfunctions – like drug addiction and crime – that the policy was designed to erode.

David Cameron's solution to a "broken Britain" would break us more. Yet that soundbite itself reveals a deep conservatism at the core of Cameronism. If Britain is "broken" today, when was it fixed? In the 1950s, when women were beaten with impunity and gays were jailed? The 1890s, when rickets ravaged the land? When? Of course Britain can be improved – it always can, like every country – but to imply we have degenerated from a lost golden age is regressive dog-whistle politics.

In the real past – as opposed to the phantasm of Tory creation – divorce was low not because every couple was living in a happy wholesome hearth, but because the door of divorce was barred shut. You don't have to read much Victorian fiction to see that no matter how much a couple detested each other, they were trapped behind binding vows. Women, of course, suffered worst, since they were largely trapped in the home, and if in desperation they tried to flee, they lost their children, their homes, and their reputations.

Far from being a time we should pine for and try inexpertly to rebuild, we should be proud we have left this behind for a more civilised and compassionate world. Isn't it a strength that we accept marriages fail, not because of wickedness or moral laxity, but because of ordinary human incompatibility? Yes, it brings some problems – but this study underlines that they are far less than the problems of imprisoning people in dead marriages, and lecturing them it's for their own moral health. Cameron's plans for married couples create a false "pro-family" sheen that prevents us from seeing how he will actually make life more stressful for parents in very tangible ways.

The one thing every mum and dad I know wants is more time to spend with their children. But Cameron is committed to pulling Britain out of the European Social Chapter as a "top priority". Britain's 10m part-time workers only have the right to paid holidays and other basic rights because of the Chapter. When it goes, so do the rights – and lots of stressed parents will suddenly have less time to spend with their kids. The Tories' market fundamentalism and anti-Europeanism trumps their warm rhetorical commitments to the family every time.

For all his upbeat let-the-sunshine-win flim-flam, Cameron's policies would simply shift more power and money towards those who already have it. The Married Couples Allowance would be a big redistribution of wealth to people who don't need it, paid for by slashing help to the poorest people who really do – from Tax Credits to SureStart to the Educational Maintenance Allowance. And all for a dysfunctional outcome.

That's the Britain we are sleep-walking towards, while we inanely discuss Gordon Brown's smile and David Cameron's bike. Isn't it time we started to scrutinise his policies, before Cameron has the power to start imposing his right-wing regression on our country?

j.hari@independent.co.uk