Call it a Budget for Christmas shoppers, if you like, a Budget for Old Labour activists, a Budget for parents and for pensioners, a Budget for small businesses getting late with their tax, for home-buyers getting late with their mortgages, for multi-nationals thinking of shifting to Dublin, above all a Budget for votes.

Insofar as it may turn out to be a Budget for the West Midlands, the brightest prospect lies in one of the chancellor Alistair Darling’s smaller multi-billion commitments, £3billion of capital spending he is bringing forward from 2010/11.

The money is destined for roads – hopefully including the M6 and the region’s lifeline links to Felixstowe and Southampton – social housing, school renewals and energy efficiency.

This is a much-needed fillip aimed directly at the construction industry, reeling as it is after the collapse of house-building. It is doubly welcome as it coincided with a warning in Sir James Crosby’s mortgage report that cash for home loans will remain in short supply right through 2010.

There is also a small mercy for the motor industry, in the deferment of the gas guzzling tax. Don’t bank on it starting a stampede to buy Range Rovers.

Mr Darling was right about one thing. There has never been a Budget like this. No Budget was ever leaked like this. The leaks were right, too – except the one pitching the “stimulus” at £15billion. It jumped to £20billion on the day.

No peace-time Budget has ever contemplated borrowing like this. None has involved such a headlong gamble on its own success.

Mr Darling drew a collective gasp of dismay from MPs when he spelt out the mountainous numbers of the government’s borrowing plans right out to 2016. Starting with £78billion this tax year, the red numbers will rise to £118billion next, followed by £105billion in 2010/11. Then they are supposed to dwindle until the government is “borrowing only to invest” in eight years’ time.

This, remember, from the chancellor who forecast in March this year’s borrowing would be £43billion. Eight months on, he is over-shooting his own calculation by 81 per cent.

These fearsome figures all assume that the great gamble comes off, that this Budget actually works. Specifically, the recession has to stop in June next year, then the economy holds steady and starts growing by 1.5 to two per cent in the election year, 2010.

That may not sound thrilling. But since this is a worldwide drama – as the chancellor repeated after each pause for breath – the way it evolves depends at least as much on events in other countries as on whether his £20billion works as advertised in Britain.

Nobody can possibly know the outcome, only that the precedents in 30s America and Japan in the 90s are discouraging.

Desperate Darling doesn’t know, you may be sure. He has his fingers crossed.

If 2.5 per cent VAT fails to deliver a sufficient Christmas shopping spree, he may have some Plan B at the back of his mind to gee things up in his Budget next March.

Forget the fiction that imposing 45 per cent income tax on anyone with more than £150,000 a year, or even the half-point on national insurance contributions, amounts to a serious effort to play back this “stimulus”.

It is a political token, a signal that New Labour is history, and a challenge to the Tories to say whether they will undo it.

It is also a foretaste of things to come as future governments of whatever party face the inheritance of Darling’s Debt.