That capitalism-with-a-conscience speech by David Cameron in Davos last night contained the moral uplift suitable for the chocolate-box setting of a Swiss resort. But here in Britain the principal Opposition must wade into some evil stuff. It's not going to be pretty, and exchanges between the Tory leader and Gordon Brown at Prime Minister's Questions on Wednesday were only a foretaste. While sensitive chaps like me cough embarrassedly into our silk handkerchiefs and look away, the Tories must play the kind of politics that gives politics a bad name - and do it with relish.

They must lodge deep in the national imagination a dismaying thought: that Britain is worse placed than its competitors to recover from the economic virus now sweeping the world. If I'm right, then Mr Brown's battles have hardly started. It's in the convalescence from this malady, rather than the illness itself, that the really ugly political argument could lie.

The virus itself can be blamed on America, Satan, sunspots - no matter. Seek the prelude where you please; the question ahead is about the aftermath. The Tory task is to move the angry inquiry forward from the geography of origin to the geography of recuperation. Which economies will heal first? Which fastest? And when chaos recedes and a weakened West picks itself up again, who will be shakiest on their legs? As we move into the new century's second decade, will Britain have moved up or down the international economic league?

If, as I believe, the answer is sharply down, the Tories must be merciless in pinning the collapse on the decade that went before; and on the man in charge of the economy throughout - the present Prime Minister. To do so won't be entirely fair, but that's politics. Mr Brown was happy enough to take the credit while credit flowed.

The politics of this crisis, unlike the economics, have yet to kick in properly. Few but a handful of party zealots honestly believe that Mr Brown is a principal author of the international banking collapse or that a Conservative government in 2007 would have reacted very differently or known how to protect us better. So for all the insult-trading across the floor of the Commons - about Mr Brown's dithering or Mr Cameron's do-nothing responses - the exchanges have had a desultory quality. The Tories don't know the cure and don't really expect us to believe they do. Labour MPs genuinely think that their leader is doing all he can, but are not so confident that his cure will work. Both parties expect the voters to conclude that nobody's sure of the answer.

Stuck in this territory it has been hard for either Government or Opposition to land serious political punches. Only two have hurt so far. First, the Tory claim that having failed to put money aside for a rainy day, the Government is running up debts whose repayment will hamper recovery when it comes. And second, Mr Brown's claim that Conservatives would let recession run its course whereas positive action by a Labour Government could lift us out of it earlier.

Significantly both claims point implicitly to the next chapter of this story. The present chapter is about the crash. The next will be about crawling from the wreckage and checking for broken bones. And, if I'm right, it is in that crawl from the wreckage, the sequel not the crash itself, that the big political story will be found.

What if, by the end of the winter of 2009-10, those green shoots fantastically conjured up by Baroness Vadera this month, really do begin to appear - but only in America? What if China and India, after catching a cold, bounce back quite fast as clients' economies begin to recover - but not ours? What if the economic trough into which Germany, France and other Northern European economies are also slipping, proves shallower for them, and their recovery comes faster? What if by spring next year the United States is demonstrably powering the global economy out of recession - yet we British still languish? What if our near-addictive past reliance on financial services hampers the restarting of the domestic economy here, because it is the City that has taken the most direct hit?

One of the ways I've been trying to comfort friends who've lost City jobs this winter is by pointing out (what is perfectly true) that there's no stigma in being fired when everyone else is being fired too. It is better to be wounded in a crowd than in isolation, when your weakness and your plight stand out as personal. Comparisons are odious and markets are cruel; failure relative to the crowd is noticed and punished more keenly than collective failure.

But if this is true of individuals, it's true of national economies too. At present the impression (fair or otherwise) is of a comparable fate facing every developed economy. When Mr Brown insists that this is a “global” problem the insistence, though tedious, rings true. There has not been enough in the British news media about how our present plight compares with that of the French, Belgians or Spanish. I have no idea how hard or easy it is to get a loan or a mortgage in Sweden or Portugal. Is unemployment rocketing in Denmark and the Netherlands too? We assume so. We are (aren't we?) assuming that although there may be local variations across the developed world, the bigger picture is that we're all in the same boat.

This version of history suits Mr Brown - and any incumbent government - tremendously well, and so far it remains more or less unchallenged. But what if the “English patient” picture of our economy begins to take shape again abroad, as did the image of the “British disease” in the 1970s? In a year's time, if credit begins to course through global arteries but we British continue to look wan, could the country be hit by a serious loss of international confidence as we keep trying to borrow more, with no sign of the gathering recovery that competitor economies are relying on to vouchsafe their debts?

It is for this bleak scenario that the Opposition must prepare public and media opinion. Come what may, the Tories will win the general election next year - but what next? Scope for action will be constricted by Britain's crushing economic plight. They'll have to explain. They'll have to blame. The blaming had best start now.

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