Well, that didn't last long, did it? The victory parades have barely begun, and already the midsummer dream is rudely shattered. No more talk of herculean efforts to win gold, no more hammering of iron rings of fire, no more warm fuzzy feelings towards our national broadcaster.

No, it's back to being depicted as a nation of slack-jawed lummoxes incapable of a decent day's work, and to Iain Duncan Smith accusing the BBC's economics editor Stephanie Flanders of "peeing all over British industry", after she failed to greet falling unemployment figures with unquestioning wonderment. So much for the legacy.

In fairness to the five Tory MPs who first pricked the bubble, via leaked excerpts from their forthcoming book arguing that we're not the nation of champions we had giddily begun imagining but "among the worst idlers of the world", this wasn't quite the plan.

Perhaps provocative references in Britannia Unchained to people preferring "a lie in to hard work" will look less inflammatory in context, or at least in season (the book's due out in September, traditional month of noses back to grindstones and party conference tub-thumping). But still, the politics of idleness deserves unpicking.

Here's a test: does the word "idle", when used by politicians, instinctively set alarm bells ringing? If so, you're probably left of centre, because it's an indisputably Tory buzzword – reeking of Norman Tebbit's father getting on his bike and rightwing tabloids haranguing welfare "scroungers", stirring in leftwing breasts the old fear of attack on the vulnerable.

But if it's that word "vulnerable" which gets your hackles up then you're probably right of centre, because vulnerability is a Labour buzzword – reeking for you of excuses to do nothing, of lily-livered bleating about why the welfare state couldn't possibly be reformed which ultimately traps those it purports to protect. You probably cheered when Eric Pickles ditched the term "vulnerable families" (Whitehall speak for impoverished families with multiple social problems) for "problem families", saying it was time to stop making excuses. For the right, the word "vulnerable" smacks of victimhood, of ducking blame and not holding individuals accountable for their actions.

Because that's really the difference between "vulnerable" and "idle". The first suggests that being broke or desperate is at least partly to do with external circumstances, which may need help to overcome; the second suggests it's your own dumb fault. "Vulnerable" resonates for those who believe in the transformative power of the state; "idle" for those who believe in the power of individuals.

And what's giving the politics of idleness a new lease of life is the marriage of an ancient Tory belief – that anyone can haul themselves up by their bootstraps, that failure means you're not trying hard enough – with a newly fashionable argument about the decline of the decadent west and rise of the industrious east.

The young Tory turks are busy weaving a narrative not just of individual moral failing (too many workshy scroungers) but of national degeneration: a sense that we've been spoiled by years of easy money and need a collective kick up the backside. It's intimately connected to austerity politics, with its inference that only rich countries can afford to go this soft.

The idea that developed nations have grown fat and lazy with prosperity, and that only the children of hungry tiger economies still understand the value of hard graft, is quietly embedding itself in political culture. Think Michael Gove raiding Singapore's education system for ideas on toughening up exams; or even the Indian steel magnate Ratan Tata, complaining last year that his company's western workers were overfond of their leisure and blaming "a certain comfort level that comes from a country that has had good times". (Tata is shortly to retire but says at 75 his life's work won't be done, a sentiment of which the Britannia Unchained quintet would doubtless approve.)

It's not clear yet exactly who these pampered slackers supposedly dragging Britain down are, beyond familiar vague complaints of a bloated public sector and kids "more interested in pop music and football" than in becoming lawyers. Perhaps inevitably, they exist now more in the realm of anecdote – the intern who thinks she's above making the coffee, young men scorning the menial jobs subsequently snapped up by immigrants – than hard fact.

And while Britain does, as the book's authors say, have unusually short average working hours, that's mainly because we have an unusually high percentage of part-timers, many of whom want fulltime work but can't find it. (Those working fulltime still do some of the longest hours in Europe.) Perhaps all those frantically juggling part-time mothers of small children – the ones who a generation ago wouldn't have worked at all – are to be deemed lazy? But there's a bigger problem with the politics of idleness than quibbling over definitions.

Hauling ourselves out of recession might indeed be as easy as demanding everyone pull their socks up, if declining GDP really was just a fancy name for indolence.

But the many dull technical reasons why value of output per worker might fall – from the shrinking of highly productive sectors like the City to the rise of self-employed freelances commanding a lower hourly rate than they did as staffers – aren't solved by simply clocking up more hours. Our challenges are not those of tiger economies, suggesting their recipe of working harder for longer for less won't necessarily work miracles here.

Yet for exploring this complicated new reality in her Newsnight report, Flanders was accused by the work and pensions secretary of "carping and moaning", running down an "incredibly robust" private sector. It's apparently fine to call individuals lazy, but not to suggest any flaw in modern labour markets.

And perhaps that's partly because doing the latter suggests we may be vulnerable (that word again) to global economic trends beyond our immediate control – trends not so easily reversed by the classic Tory formula now being touted for unleashing our inner tiger, namely slashing employment regulations and cutting benefits. Idle, or vulnerable? The story we believe about ourselves has wider implications than we think.