Alastair Campbell has a very interesting blog this morning, which has been picked up because of its attack on Andrew Marr for telling David Cameron today that he is "on a roll!".

But there is another, more important element: a full-frontal attack on the Murdoch media empire. This is significant because Campbell was key to Blair winning the Sun's support in the 1997 election.

And close watchers of Campbell since the Sun switched to the Tories last year might have noticed that he has held back from launching a full-scale assault on the Murdoch press, to which he ramains close. Today, however, he says this:

As the news bulletin made clear, the weekend polls indicate that the outcome is likely to be in hung parliament territory. Yet the tone of the coverage is all playing into the "unstoppable momentum" strategy for Cameron, led by Murdoch papers and TV. It is sad to see parts of the Beeb fall in behind, especially bearing in mind what is going to happen to them if they end up with a Tory government whose media policy has been shaped to suit the Murdoch agenda.

A piece I wrote in November about the Sun's relationship with Labour included this story, based on Campbell's diaries:

It was in the summer of 1995 when, ominously clutching a kettle full of boiling water, Neil Kinnock erupted in fury at Alastair Campbell. The old friends were holidaying in France and the former Labour leader had just learned of Tony Blair's decision to fly to Australia as part of his extensive campaign to win the support of the Sun and its owner, Rupert Murdoch. In his diaries, The Blair Years, Campbell recalls Kinnock saying: "It won't matter if we win as the bankers and stockbrokers have got us already by the f*****g balls. And that is before you take your 30 pieces of silver." A victim of the Sun throughout his leadership of Labour, Kinnock spoke from the heart. "You imagine what it's like having your head stuck inside a f*****g light bulb then you tell me how I'm supposed to feel when I see you set off halfway round the world to grease him up," he said, referring to the tabloid's front page on polling day in 1992, which declared that, if Kinnock were to win, the last voter to leave the country should "turn the lights off". When Campbell protested that he and Blair had given nothing to Murdoch, Kinnock countered prophetically: "You will. And he will take it. You will get his support and then you will get the support of a few racist b*******, and then you'll lose it again the minute that we are in trouble." And so it came to pass. After an awkward 14-year interlude, the Sun has now returned to doing what it does best: bashing Labour.

Looking back at his diaries, even Campbell may now agree that Kinnock was right. But so is Campbell. Labour has learned that support came at a price. If the Tories win this week, they will learn the same lesson one day.