Sean O'Grady: If you get all the bad news out at once, the only way left to go will be up. Or will it?

Alastair Campbell, who understood such matters better than most, said that all governments need a "narrative" – a simple, straightforward way of saying what they are about.

Whether by accident or design, the coalition government seems to have written its narrative without too much difficulty. It is this: "Don't blame us for all the painful cuts we're about to inflict on you. Blame Gordon Brown."

It's the "trashing" David Miliband warned Labour about yesterday. The long-awaited line that the new Chancellor had discovered hitherto-undreamt-of horrors in the darker recesses of the Treasury was delivered yesterday. George Osborne declared that "we are finding skeletons in cupboards and decisions taken at the last minute". Outgoing Labour Chief Secretary to the Treasury, Liam Byrne, didn't help his own side by leaving a jokey note behind about there being no money left.

Many previous governments inheriting an economic mess – Labour in 1964 and 1974, the Tories in 1979 – have been able to use the line that they're clearing things up. But this time the numbers will be so awesome that a terrified nation will be expected to acquiesce in whatever cuts Mr Osborne and David Laws have planned for them, for fear of worse.

The temptation for Mr Osborne will be to follow the standard practice of any business in trouble. A new chef exec arrives and "kitchen sinks" all the bad news, getting it all out of the way. After that, the only way is up. The by-elections can be lost while the Government holds its nerve and waits for the recovery that will offer them a second narrative: "We kept our promises. We have saved the economy. We have sold off the banks and made money. Now vote for us."

So when he comes to deliver his Budget on 22 June expect Mr Osborne to throw everything into the sink – the £52.5bn of spending cuts he couldn't tell us about before; the hikes in taxation he couldn't have foreseen. In this enterprise Sir Alan Budd's new Office for Budget Responsibility will do its bit. Shaving 1 per cent off the growth forecast for next year left behind by Alistair Darling, from 3.25 per cent to 2 per cent say, will add another £10bn to next year's borrowing. Maybe not this time, but soon, we will also be told the true cost of all those PFI projects, "off balance sheet" liabilities amounting to trillions. Then the true unfunded costs of public sector pensions will be thrown into the sink.

Given all that, and the alternative of a sterling crisis, soaring interest rates and spiralling mortgage bills, who wouldn't argue with an immediate £6bn start on reducing the deficit?

Yet one is reminded of some stern warnings about such a policy issued during the election campaign. "It would be reckless to plunge the economy back into recession through the immediate large-scale slashing of public services and jobs because the Government's deficit would widen instead of contract." Or "There is a real danger of the UK going into a double-dip recession."

The words, of course, of Vince Cable, hailed on his first day at the Department of Business as an "economic star". When it comes to political narratives, what's past is prologue.