Get ready for a fiscal horror show

In the Treasury they call budgets and pre-budget reports (PBRs) and autumn statements “fiscal events”.

This is one heck of a fiscal event. And if you were wondering why almost the entire contents of it have been strategically dribbled out over a week then at about 1pm, after a half hour preamble on various growth wheezes, you will find out.

The chancellor will have to read out the independent Office of Budget Responsibility’s borrowing projections. It will be the most unwelcome piece of independent advice since Thomas Becket’s suggestions to Henry II.

Even the collapse in growth prospects will pale compared to the fiscal bloodbath that is coming. Only the PBR of August 2008 will rival the extra red ink deposited by the Treasury printers.

As then, the chancellor will shove all the blame on to an external event, the eurozone crisis now, Lehman’s collapse then. This will be fair up to a point, but masks the fact that the fiscal plans were blowing off course well before then as growth failed.

The numbers stand to be mind-blowing and gamechanging. The FT splash suggests a structural deficit of £30bn rather than a surplus of £6bn in the structural current deficit by 2014/15.

Reuters numbers suggest an extra £86bn of borrowing in four years, taking borrowing well above the cash amount planned by Alistair Darling, by £2bn this year, and tens of billions in later years.

Shocking. We’ll know just before 1pm-ish if it’s true.

The coalition will blame the euro. Labour will blame premature harsh austerity. Standard & Poors and co won’t care.

It will take a Herculean suspension of disbelief for Britain not to be put on negative watch for its AAA. That is because Britain is being judged not just on the credible commitment to deficit reduction, but also on whether the economy will grow.

Either way, Britain will sport deficits that in cash terms the Chancellor and PM suggested pre-election made us close to Greece.