George Osborne’s political career should be lying face down, lifeless, bobbing in the Thames. His statement last week should have been rebranded “The Comprehensive Review of the Failure of Austerity”. The Tories’ central pledge at the last election, after all, was that the deficit would be erased, wiped out, vanished over the course of this Parliament: there should have been no alleged need for further cuts after 2015.

But everything those who were smeared as “deficit deniers” predicted would happen back when David Cameron and Nick Clegg began cavorting in the Rose Garden has come to pass. Austerity has acted like a growth-seeking missile, leaving Britain embroiled in a longer economic crisis than the Great Depression itself. The underlying deficit is bigger this year than it was the last; Osbornomics has left the Tories borrowing £245bn more than they projected. Here are the calamitous results of a lethal combination of a shrinking economy, suppressed demand and stagnant tax revenues. Companies are sitting on monumental cash piles worth hundreds of billions which they are not investing. Meanwhile, the average worker faces a pay packet shrinking at the fastest rate in modern British history. No wonder that Osborne’s approval rating languishes somewhere around minus 40.

And yet, and yet. The Chancellor’s default facial expression may be set to smug, but – given the circumstances – his performance in the Commons last week was assured, confident, even cocky. No wonder. Even as austerity has failed on its own terms, the Official Opposition has not so much missed open goals as fled in the opposite direction. The Tories’ message can be summed up in one easily digestible sentence: “We will cut the deficit by reining in public spending, stopping hard-working taxpayers subsidising the indolent and the workshy by cutting welfare, and we will live within our means.” Labour’s current muddled message would take several confusing paragraphs, filled with caveats and clarifications, covered in scribbles and crossings-out. Osborne has cut too far and too fast, they say, but we will stick to his plans. The Tory approach to cutting social security is wrong, though many of their underlying principles are right. Many of their cuts are as cruel as they are unnecessary, but we will not reverse them.

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Perversely, this farcically disastrous Chancellor has been allowed to make the political weather, constantly leaving Labour in a defensive posture. His declaration that people thrown out of their work must wait for seven days before getting benefits is a classic example. Working people pay into national insurance and deserve to be supported when their boss sacks them, Labour should have said. The average wait is already more than three weeks as it is. This will only benefit legal loan sharks – who a million families now turn to – and lengthen the queues to food banks, who now cater for half a million people in the seventh-richest country on earth. But Labour did not make these arguments. Ed Balls instead accepted the underlying logic of a longer wait – with caveats, of course.

The Tory strategy is to crucify Labour over social-security spending, aided and abetted by right-wing propagandists posing as journalists who hunt down extreme, unrepresentative examples and pass them off as the tip of a feckless iceberg – say, a woman with 45 kids and a giraffe on benefits, as my colleague Mark Steel puts it. But as a poll published in this newspaper at the start of 2013 showed, thanks to our media, the public are chronically misinformed about social security: about who gets benefits, how much they are worth, and the real level of fraud (around 0.7 per cent). The more they know the reality, the less likely they are to support life-destroying cuts.

Rather than accepting the Tory terms of debate on social security, then, Labour should be launching the mother of all campaigns to educate and inform. Most social-security spending goes quite rightly on elderly people, who have paid in their whole lives. Most working-age benefits go to people in work, like tax credits, which are a subsidy for low pay. Housing benefit – which has jumped by £2bn under this Government – lines the pockets of landlords who can get away with charging rip-off rents, knowing that you and I, the taxpayer, will step in.

To bring down social-security spending in a sustained way, Labour should say, we will address the root causes: taking on low pay with a living wage; controlling rents as well as allowing councils to build; and an industrial strategy to create hundreds of thousands of jobs, not least in renewable energy as Germany has done. Such a message would undercut the prejudices that the Tory offensive depends on.

But instead, Labour’s leaders – pessimistic as they are about the prospects of shifting public attitudes – fail to challenge myths, and even occasionally feed them. It is utterly self-destructive. The more “skivers” or “shirkers” are inflated in people’s minds, the bigger the potential pool of Tory support. After all, if you really want to give “scroungers” a kicking, you will always trust the Conservatives best to do it.

And here is the fatal flaw in the Labour leadership’s strategy. They think they are buying back credibility, rather than shoring up policies that should be seen as sunk, ruinous, shredded. By failing to offer a coherent message, they risk a sense of “at least you know where you are with the Tories” bedding in. But the cost is not only to Labour’s electoral prospects: it will be to the working, disabled and unemployed people whose pockets will continue to be emptied.

A generation of plummeting living standards beckons – unless the Labour leadership’s failure to challenge a hijacking of the financial crisis to roll back the state is countered. Last week, more than 4,000 people attended the People’s Assembly coalition against austerity, and decided on a rolling programme of action. Learning from the success of UK Uncut in forcing tax avoidance on to the political agenda, a day of peaceful civil disobedience will be held on 5 November. The gentleman’s agreement of British politics has to be sabotaged: our futures and those of our children are at risk. That’s not hyperbole. It’s the appalling truth.