Owen Jones: What happened to idealism?

Given that one running joke is that I look like I should be delivering newspapers rather than writing for one, it might jar for me to get dewy-eyed about politicians of the past, but hear me out.

Take a moment to compare the current crop of political "heavyweights" to, say, the leading lights of post-war Britain. In the first majority Labour government, headed by Clement Attlee, there was Nye Bevan, ex-miner, fiery orator and founder of the NHS; Ernie Bevin, who started work as a labourer aged 11, and became the country's most powerful trade union leader before ending up as Britain's representative on the global stage; and Herbert Morrison, an errand boy who went on to become deputy prime minister.

All had lived working-class lives; their experiences had informed and driven their political passion. Bevan, for example, had seen miners stricken by ailments but denied access to decent healthcare.

Even Blairites these days pay homage to him, but they would have been among his bitterest critics then: Bevan was a man of uncompromising conviction, resigning when Hugh Gaitskell introduced prescription charges in his beloved NHS.

And look at where we have ended up. An increasingly technocratic, professionalised political élite, who could not fail the "imagine them down the pub" test any more painfully. According to the Sutton Trust, well over a third of new MPs elected in 2010 were privately educated, compared to 7 per cent of the rest of the population. A stunning one in five new MPs already worked in the Westminster bubble before their election; and only one in 20 MPs hail from any form of manual background. During the expenses scandal, MPs – who are in the top 5 per cent of earners – privately whinged that they were paid less than City bankers or lawyers, as though it was just another upper-middle-class profession, rather than a service or duty to the community.

The political establishment is not only drawn from increasingly narrow backgrounds. The differences between them have narrowed so much that is often nuance, rather than substantial policies, that divide them. Appearing on Question Time last week with Yvette Cooper, Iain Duncan-Smith and Charles Kennedy, it struck me just how suffocating the political consensus has become. Kennedy – who once courageously spoke out against the obscenity of the Iraq War – could not bring himself to challenge the Government's line on Israel's onslaught on Gaza.

When I pointed out that it was Israel that had broken the ceasefire, and asked which people would tolerate decades of occupation, siege and illegal settlements, it was hugely appreciated by the audience – simply because it was a widespread view that no mainstream politician had attempted to articulate. In a frustratingly curtailed debate on welfare with Duncan-Smith, I found myself despairing that I was being forced to do what the Labour leadership was still failing to do. Opposition, I think they call it.

Indeed, on the key questions of our time, many senior politicians are at one. They are committed to devastating cuts, differing only on degree and timing. They believe in the supremacy of market economics, including allowing private profiteers to make a fast buck out of our public services. They oppose challenging the supremacy of the City, or making Britain's booming wealthy pay a significantly higher share of tax. Mission, belief and passion have been stripped from politics so that – even at a time of crisis – it risks becoming a bland managerial contest. Instead we have politicians with "values" such as "fairness". Who ever campaigned for unfairness?

Watching David Miliband being interviewed on TV yesterday, I was struck by how he was the epitome of this professionalised, consensus politician. That he is regarded as more effective than his brother has always been – for me, at least – the great mystery of British politics.

Before 2010, he was best known as the man who bottled out of challenging Gordon Brown and who was snapped carrying a banana. He has never worked outside of politics. He speaks and writes with often bafflingly vacuous prose; like "meet the needs of tomorrow rather than yesterday", for example. Reading his entry in the Register of Members' Interests, it is difficult not to wonder how he finds time to represent his constituents: since being defeated in the Labour leadership contest, he has raked in tens of thousands of pounds advising corporate outfits and through speaking engagements all over the world. If the failures of modern politics were to be summed up in one individual, David Miliband would be a leading candidate.

There are still idealistic young things who have a sense of wanting to rail against injustice. But among them are shamelessly ambitious politicos, too, who'd happily trade an aunt on eBay for a parliamentary seat. You can see them on Twitter, sending the sort of anodyne tweets in their early 20s that might be expected from a politically generic shadow minister.

No wonder George Galloway stormed to victory in Bradford earlier this year, that the odds on Respect in the upcoming Rotherham and Croydon North by-elections have narrowed, that Ukip has surged in the polls, and Boris Johnson – despite his adherence to Tory dogma – attracts such an unlikely following. All are seen to defy the orthodoxies and woefully uninspiring styles of the political élite. The electorate is thirsty for anything that defies the sterile Westminster consensus.

Historically, it has been Labour's role to challenge wealth and power. If its leadership is unable to do so – whether it be through lack of courage or conviction – a vacuum will be left. In such turbulent times, that vacuum will be filled. The cosy consensus of the professionalised political élite may be suffocating, but it is not sustainable. A perceptive eye can notice the cracks and observe that – with a bit of a shove – the whole edifice could shatter.