Sometimes journalists get so obsessed with news that isn't that they completely forget that which is.

Yesterday was one of those occasions.

We all knew that Alastair Campbell was going to resign this summer. He'd as good as told us a month ago. Yet none of us expected it to happen yesterday. And despite the fact that one of the most important players in rebuilding Iraq had been assassinated along with ninety-odd others, and that an inquiry into Princess Di's death had finally been announced (a natural lead for many papers and programmes on all but the most sensational of news days) the fourth estate only had eyes for Ali once the story broke.

(A News 24 political reporter, Vicky Young, was doing a live interview - what's known in the trade as a two-way - from the News Online newsroom when our central newsgathering people announced Campbell's resignation over the tannoy. The cheer that went up from some of my colleagues sitting just feet behind her would have been enough to rattle all but the most accomplished of broadcasters, but the seemingly unflappable Vicky didn't miss a beat as she calmly finished her sentence and went on to break the news to viewers).

All the journos agreed it wasn't really the day's biggest story. All the editors said it was. No prizes for guessing who won. And so the BBC's giant home newshunting machine zeroed in on Downing Street.

Yes, he's been a central figure in British politics for the past nine years. Yes, his departure will likely have a major effect on Blair's presidency. But we already knew he was leaving. And we knew he wasn't going yet.

The confusion about what the story actually was could be seen in coverage across all media outlets - not just the BBC. A headline or caption like "Campbell resigns" would be immediately followed by a first line reading "Tony Blair's chief spin doctor Alastair Campbell has announced he is to resign."

So had he or hadn't he?

Well, yes, he was going... but not quite yet.

It was an enjoyable enough story to cover, and the media came together to make it feel like something important was happening, but I'm still not convinced that it was quite as weighty as we made it out to be.

After all, what did we know at the end of the day that we hadn't known at the start? Very little really, but that shouldn't be surprising from a government notorious for announcing new initiatives and funding increases several times over. Why shouldn't they do the same with resignations?

It was a perfect final flourish from Campbell showing that, despite the row over sexed up Iraqi dossiers (which was with more than just the BBC) and the Hutton Inquiry (the publication of documents from which his resignation completely - conveniently - smothered) and allegations that the government had spun itself out of control, he still had the British media in the palm of his hand. We were all singing his tune.

No doubt we'll all sing along once more when he finally leave Number 10 for the last time in a few weeks' time.

And you know what? No one will think to ask why.