So the love affair between Tony Blair and Margaret Thatcher is finally over.

Ten years after Baroness Thatcher was ousted as Tory leader, the prime minister has declared it is time to move on.

And, superficially, it is the issue of Europe that has been the cause of the split.

Mr Blair was clearly stung by Lady Thatcher's attack on his support for a Euro army, which she has branded a "monumental folly."

Change of heart

And he has responded by insisting that, while many of the things she did in the 1980s were good for Britain, she also did great damage.

His apparent change of heart will delight many of his backbenchers who have always been deeply uncomfortable with the notion that he was somehow her natural heir.

They were dismayed at his obvious admiration for the Iron Lady and the fact that he turned to her before anyone else for advice immediately after his 1997 election victory.

And they have long been looking for him to distance himself from her and her legacy.

He may not have gone that far - and his admission that much of what she did was right will still anger many Labour MPs - but he has taken a decisive step out from under her shadow.

Fundamental differences

The Tories will also be delighted that the prime minister has now attempted to distance himself from their most successful post-war leader, believing it gives them greater opportunity to attack him.

And, while Europe was the almost inevitable catalyst for the split, it is also clear that there are more fundamental differences which the prime minister wanted to spell out.

It was probably no accident that his recantation of Thatcherism came on the same day he unveiled a white paper on investment in public services.

There was nothing new in the document and many wondered why such a device was being used for what was clearly a hugely party political stunt.

Election on horizon

But the answer is simple. We are in the middle of a general election campaign and the prime minister is mapping out his platform.

He knows his previous admiration for Lady Thatcher has lost him support amongst Labour's heartland voters and that many are still unsure of exactly what he stands for.

So he has spelled it out with greater emphasis than ever before. He is for Europe and against the Tories' Eurosceptic stance but, more importantly, he is for massive investment in public services and he wants voters to understand that this is at the core of his beliefs.

He wants to move the pre-election debate away from Europe and onto what he believes is more fertile electoral ground for him. And he wants to paint Labour as the party of investment and the Tories as the party of cuts.

The effect of all this is to widen the famous "clear blue water" between Labour and the opposition. And it is the clearest possible sign of exactly how the real general election campaign will be fought.