What on Earth has happened to Gordon Brown over these last few days? The man who until only recently was seen as a dour, plodding, unsmiling ditherer has suddenly blossomed forth in the most unexpected way.

At Prime Minister's Question Time in the House of Commons he has been giving the Opposition leader David Cameron as good as, if not better, than he gets.

He is striding around with a broad smile on his face and a spring in his step, something that was not noticeable only a week earlier.

The PM even cracked a joke. Unheard of!

His great clunking fist – as described by Tony Blair – has at last revealed itself.

It is not as if the opinion polls are showing Labour in the lead, or anything like it, although they do seem, at last, to be moving in the right direction, from Labour's point of view.

Part of this transformation in his demeanour, I think, has been due to his bold, even reckless, reshuffle earlier this month in which he restored Peter Mandelson to the Cabinet. But a far more likely explanation is that he is actually relishing dealing with the global financial crisis without Tony Blair continually looking over his shoulder, and taking the credit when things go right and blaming others when they don't.

What is more, the undercurrents within the Parliamentary Labour Party, designed to oust him from office, have subsided and virtually disappeared.

A few nonentities resigned from the Government, or were sacked, during a turbulent summer as a result of this disloyalty. Now, they may well be regretting their actions.

A fortnight ago, the Labour Party in Parliament and beyond looked broken-backed and in danger of returning to the bad old days of the 1980s, when many believed that the party was in such a parlous state that it would never be elected again.

But the cataclysmic events of recent days have put new spirit in the party, in a way which could make it an effective fighting force again.

Cameron would therefore be a fool to assume that the next General Election is in the bag for the Conservatives.