Leading article: 'It's who you know, don't you know?'

A year after becoming leader of the Conservative Party, David Cameron declared that the Tories were the party of social mobility, of progressive politics. He described as "a terrible, unforgivable fact" that a child born into poverty in 1990 is less likely to escape from poverty than a similar child born in 1970. Yet this weekend we learned that the Prime Minister is giving an internship in his office to a neighbour and that he personally gives internships to the children of friends and supporters. "I feel very relaxed about it", he said.

Is there any discrepancy between his protestations five years ago and his actions now?

When the issue surfaced some weeks ago, Nick Clegg acknowledged that he had been a beneficiary of helpful connections, but sought to point out that a blemished past should be no obstacle to a more virtuous future. It is merely human for any of us to help people we know ahead of those we do not, but the very fact that the big-picture consequences of such helpfulness seems not to have occurred to the Prime Minister is in itself a problem.

There are party-political reasons why Messrs Cameron and Clegg should be trying to put ideological distance between one another just now. Mr Clegg is genuinely, justifiably, angry about the way he has been depicted by the opponents of AV in a referendum campaign that is becoming worryingly personal. This mood may or not blow over after the referendum.

The issue of social mobility, though, is a less transient and ultimately much more important one, but, judging by Mr Cameron's remarks, it looks more like a stick-on extra than a guiding force for a reforming government. The media's interest may look like a one-weekend wonder, but the problem really is as grave as Mr Cameron acknowledged in 2006. Social mobility has stalled and there for many reasons.

The decline of the manufacturing industry, with the opportunities it offered ordinary individuals to acquire skills and profit by them, is pre-eminent among these. The abolition of grammar schools – whatever else that may have achieved – has removed an escape route from deprivation for many bright, poor children. There are many distinguished professionals in positions of influence now who would, growing up in Britain today, find it harder to acquire the same education as they got from the grammar schools. That, in turn, enabled them to attend the best universities. There are other systemic inequalities too. The concentration of one growth industry, financial services – and indeed, the media and politics – in London does not, obviously, provide the same job opportunities for the North as for the South-east.

In the light of these large factors, does it actually matter whether the Prime Minister or anyone else gives internships to people he knows? As he hastened to make clear, his lucky new intern is a farmer's daughter from a comprehensive. If giving unpaid internships is wrong – and they do give an unfair advantage to those whose parents can support them – then it is something that many liberal institutions and individuals are guilty of, not excluding this newspaper, and some Lib Dem MPs. The phenomenon is probably not so much important in itself, as for what it does to consolidate inequalities that exist for other reasons.

Mr Cameron's own history is a case in point. He got work experience in his father's stockbroking firm – "a definite leg-up internship" – and contacts smoothed his path into a Commons internship, his first job with the Conservative Research Department and his Carlton Television post. Everyone agrees he is very talented, but there is a bit of a pattern. The following of his own "lucky" upbringing with his professional success is no accident.

In this context, Michael Gove, the Education Secretary, is doing as much as anyone in government to change things. One of the formidable handicaps state school pupils used to face in obtaining places at good universities and in sought-after apprenticeships was that schools directed them to soft subjects in which they could more easily obtain high grades, rather than to single science subjects, classics and languages. That may now change. Increasing incentives to the very poorest to remain in full-time education is another useful step.

What this argument about interns does do is usefully raise the much wider, crucial issue of social mobility. It is still unforgivable that children growing up now find it more difficult to escape from poverty. And unless Mr Cameron can recover his old sense of indignation, the Government's record will remain flawed on one of the most important issues of all.