Michael Portillo is spot on in his analysis of the Blair effect. Despite his unprecedented electoral achievements, commentators and politicians seem to forget the scale of the impact Blair has had on politics. Nothing today is as it was. The normal rules of politics were suspended from the day in July 1994 when Tony Blair was elected leader of the Labour Party and, despite everything which has happened since, they remain suspended. Blair is a politician - in purely tactical terms - of unsurpassed genius. Portillo gets to the heart of it:

Blair, like Margaret Thatcher before him, wins elections not because of his popularity but because he started by destroying the opposition, leaving the electorate with no alternative. Both he and Thatcher demolished the intellectual self-confidence of their opponents, leaving them rudderless and squabbling among themselves about which way to go.

Blair was able to occupy the middle ground of politics and to appeal to the middle classes in a way that Brown could not have. The Tories have been left having to choose between mimicking Blair and opposing him from the right. No wonder they are in disarray. Even Blair’s war on Iraq, although it carried political risks, had the effect of further marginalising the Conservatives because they had nothing distinctive to say.

When divisions consumed the Labour party in the early 1980s it split in two. Many MPs defected to the new alliance of Social Democrats and Liberals. The disaster of the split coming on top of the catastrophe of Labour’s general election results produced the necessary sense of panic. Labour had to accept huge policy changes. It entered a pact with Blair, a man capable of leading them to victory.

The split in the Labour party was the catalyst for change. The tragedy of the Tory party is that it will not split. The factions will lock horns and stay together.

It is sheer nonsense to suppose, as the more deluded Labourites think - I should say hope - that when Brown becomes PM he will reveal himself to be left in tooth and claw, the prince over the water who comes to the rescue of the left. The main difference will be one of tone, and inaction.

But. And it is a big but. The tone matters. Brown will not be able to place Labour so squarely in the middle, in art because he doesn't want to, and in part because he derives much of his support within the Labour Party from the very fact that he is seen as a Labour man through and through, in contrast to that interloper, Tony Blair. That means that when he takes over, politics will return to something close to normal - Labour versus Conservative, a battle which we have simply not had since 1994.

As things stand, however, Labour will win that battle, albeit by default. The Tories have not yet grasped that, however great the opportunity presented to them by a Brown premiership, they are not remotely in a position to capitalise on it. The Tories are - literally, as last Thursday showed - unelectable as a serious party of government. Worse, they have made amost no progress on 2001. If they think securing 32.3 per cent is progress, they are heading for a fourth defeat.

But if they learn the right lessons from Thursday, and from the likely battlelines of the 2009 election, then we are in for an even more fascinating time ahead.