Less than a fortnight ago I wondered whether we might see a return to Keynesian-style cash injections to buoy the real economy and more specifically construction. I recall other similar comments in the media.

Now it seems from stories in the FT and the Telegraph that this thought may become reality. Though I suspect that the scale when measured against the massive construction sector will in the end prove more muted than the headlines might suggest.

But leaving issues of scale to one side, this may be the best news for construction since the credit crunch bit a year ago. And by bringing forward budgeted spending Chancellor Alistair Darling may spare construction the worst of recession.

I'd be mad to speculate on how much cash might go where to fill the holes that are appearing in the industry's workload. Also there is no real consensus, outside of private housing, on how deep the holes in the private sector construction work might be.

The industry should also, as I am sure it will, moderate its joy if Mr Darling does produce a large rabbit from the hat. You can only turn cash into construction activity so fast. The effectiveness of any spending will rest on what and how smartly the money is spent.

And, lest those with shorter memories than mine (few I'm sure) forget, the last recession in construction was eased by a quasi-Keynesian boost under the John Major Government.

A huge boost to spending in the early 1990s saw the annual increase in infrastructure output rise by about £5 billion in today's money between 1989 and 1993. And as that spending eased it was followed by a lift in spending within other public sector construction in the period 1994-95.

We don't know how deep this construction recession will be. The views vary widely as is clear from the spread within the forecasts recently mentioned here.

More importantly, we don't know how much money Mr Darling will pump into construction.

So, while a boost from the public purse is welcome, certainly in the house-building sector, it is no guarantee that it will head off a recession. Certainly the efforts in the 1990s failed to do so.