The odd thing is that it is left-wingers, not Cameron, who have lurched to the right

ANTHONY BROWNE It's not hoodies. It's not single mums. It's not even jittery City whizz kids down to their last ten million No, it's lefties we should be furrowing our collective brow about. We shouldn't worry about the threat they pose to society (even though successful countries can survive anything except civil war and socialism). It's the fact that they appear to be suffering a crisis of faith.

It is a crisis which disproves the claim that while the Right won the economic arguments, the Left has at least won the social ones. And it helps explain why our Labour Prime Minister demanded 'British workers for British jobs.' And why the question should be not, 'Why is David Cameron lurching to the right?', but, 'Why is everybody?'

Evidence that it is a crisis of faith — rather than merely a change of mind — is that lapsed left-wingers, like lapsed Catholics, have a tendency for confessions and exegeses. The latest addition to a nascent genre of literature is the excellently insightful The Fallout: How a Guilty Liberal Lost His Innocence (out this week) by Andrew Anthony, star feature writer of the Observer newspaper. In the US, the confessions of lapsed liberals are becoming a significant genre of publishing.

The liberal Left has suffered the double whammy of the collapse of the Berlin Wall, bashing their economic beliefs, followed by the collapse of the twin towers, bashing their cultural ones. It was September 11th — or at least the anti-Western, pro-Islamist apologia for it — which started Anthony's doubt. But it was a mugging that finally did it for him Not the metaphorical mugging by reality, but an actual one. He intervened when a schoolgirl was viciously attacked by a gang of other schoolgirls as passers-by just looked on, and was disturbed that everyone excused the attackers' behaviour, blaming it on poverty and poor education, rather than condemned it. He's not the first apostate at the Observer. Its columnist Nick Cohen recently provoked near-panic in the liberal Left with his powerful tome What's Left? How Liberals Lost Their Way.

Of course, the journey from left to right is very well travelled, and well remarked on. Just think of former Guardian columnist Melanie Phillips, Christopher Hitchens or the American neoconservatives — who came, of course, from the political Left. The 19thcentury French monarchist Francois Guisot sparked a rash of copycat quotes when he said that 'Not to be a republican at 20 is proof of want of heart; to be one at 30 is proof of want of head.' The French prime minister Georges Clemenceau swapped the word 'republican' for 'socialist'.

The Left often attributes the rightwards drift to the burdens of middle age — acquiring a house, a higher salary and kids makes you appreciate property rights, lower taxes and law and order. But it's not acquiring property that challenges beliefs, but acquiring wisdom.

The reason so many go from left to right is the realisation that the Right is, well, right. About pretty much everything. You just can't buck the evidence. That's why you don't get books from reconstructed right-wingers proclaiming that at last they've realised the Left is right. Instead, the Right is on the rampage, with books such as James Delingpole's How To Be Right: The Essential Guide to Making Lefty-Liberals History.

Being left-wing has a powerful emotional appeal — it seems morally better, which is why people find it so hard to leave — but it is intellectually less fulfilling. And the idea that it occupies the moral high ground is largely an illusion.

I won't dwell on the economic arguments — even Neil Kinnock acknowledged that Margaret Thatcher was right. Blair kept her union legislation not just out of political opportunism but because he knew it worked. Although he was elected on a campaign to scrap the NHS internal market, Blair learnt from experience that nothing else worked, and brought it back.

But what of the social arguments? The Left was definitely right on basic moral issues, particularly on promoting tolerance — whether it be gay rights, women's rights, or combating racism. But on most other social issues, it was wrong. About the causes of crime, family breakdown, the dangers of welfare dependency, personal responsibility, and the drawbacks of multiculturalism, the Right was right. When lain Duncan Smith visited a rundown estate and was challenged: 'What are you doing here? This is Labour territory,' he replied: 'Yes, and look around you.'

Increasingly those on the Left are agreeing. Many, whether Frank Field on welfare reform, Alan Milburn on public services, Polly Toynbee on low-skill immigration, or most Labour home secretaries on human rights, have reluctantly thought themselves into traditional right-wing positions. It looks increasingly as if Gordon Brown has seen the Right light too, given his predilection for stealing Cameron's ideas.

Across the policy spectrum, our supposedly left-wing government is adopting right-wing policies, and not just as a result of political opportunism. Rather than chanting the joys of diversity, it is promoting social cohesion, whether by flying the union flag or curbing translation in public services. Trevor Phillips has given us all permission to show right-wing scepticism about multiculturalism.

The government pursues curbs to lone parent benefits and disability benefits because it realises the moral hazard of languishing on welfare. Faced with concern about the breakdown of respect, it is talking and occasionally acting tough on discipline and law and order.

Whether it is market forces in public services or multiculturalism, the Left first successfully demonises right-wing policies and then, when its own ideas fail, it adopts them without apology. The Left's great triumph has been to remain credible after adopting policies that it had demonised; the Right's failure has been to win the arguments but lose the debate.

A crisis of intellectual confidence on the Left would, at first glance, be a boon to the Conservatives. But the opposite is true: it is easier for Labour to change policies than for the Tories to scrape off the mud thrown at them.

Tony Blair could show Labour had changed by ditching Clause 4. But Clause 4 was a matter of great indifference to voters and utterly intellectually discredited. Losing it was a win-win situation. The problem for Cameron was that, whether on immigration, crime or Europe, he had no flagship Conservative policies to ditch which were both manifestly wrong and utterly unpopular. So he remained silent about them, leading to the bizarre position that Brown was outflanking the Tories to the right on traditional Tory territory.

Last week, Cameron broke that silence. But was it a lurch to the right? Not in any meaningful sense, since there was no change in policy, and Cameron was just playing catch-up with Labour. It was more a rebalancing — the public are concerned about hospitals, schools, crime and immigration, and now Cameron has talked about all four.

But if voters want right-wing policies, should they go to the political tribe that pioneered them, or the one that demonised them and then had a change of mind? The answer to that will decide the next election.

Anthony Browne is director of Policy Exchange.