Brown the bungee jumper on the way up

Gordon Brown's bungee ride from political hero to zero and back again would be remarkable in any circumstances.

That it apparently took a banking collapse and looming recession for him to achieve it confounded most conventional political wisdom.

As Chancellor, Mr Brown prided himself on economic prudence, controlled public borrowing and quarter after quarter of economic growth producing low unemployment and even a basic rate income tax cut.

But after a brief honeymoon period in No 10, it seemed that record might count for nothing in the face of David Cameron's resurgent Tories and poll ratings that put his party on its lowest ever ratings. There was open dissent among Labour MPs and talk of a leadership putsch against him.

A predicted dismal showing in the Glenrothes by-election was supposed to be one of the triggers to oust him, following poll disasters in Crewe and Glasgow East.

Now he is facing a global financial collapse, dire forecasts that the UK may fare worse than many competitor countries, a sinking pound, a stock market at times in freefall - and suddenly his popularity is bouncing back and the Government coasts to a comfortable win at the ballot box.

How much impact yesterday's shock 1.5 per cent cut in interest rates had on the Glenrothes result may be impossible to calculate, but even if all it shows is that Mr Brown has become a lucky politician again to benefit from such a polling day boost, Labour MPs will be happy.

The banking crisis has given Mr Brown once again the chance to perform on the stage he knows best, rolling up his sleeves to plunge into the minute but vital detail of rescue packages and world financial initiatives.

And by constantly urging banks to pass on rate cuts, and oil companies to cut petrol prices in line with the fall in crude oil prices, he can stand again as a champion of voters against the might of big business.

Whether by luck or judgment, he has manoeuvred a position where it appears that City fat cats and wheeler-dealers and not the Government are to blame for the economic mess, although the issues of banking's systemic failure and a lurch into recession for the UK, while linked, are arguably quite separate in their cause and effect.

As he put it this morning: "People are prepared to support governments that will help people through the downturn."

In Scotland, Mr Brown also benefited both from his local popularity - the poll was in the next-door constituency to his own - and the fact that the SNP administration's ability to respond to a world economic crisis was called into question and gave another target for Labour to aim at.

Mr Brown is firmly out of the woods - for now. Any talk of getting rid of him from No 10 would be laughed out of court among most Labour backbenchers.

However, the wider lesson of the Premier's violent swings in popularity will not be lost on those still stuck in perilously close-fought Westminster seats.

What goes up can come down and as the economic slump bites, voters may yet turn their anger back on the man in No 10.