The other election conundrum

When to call an election is one problem, but here's another - when do you uncall an election?

Gordon Brown will want to keep the option of an Autumn election as long as he can. But the longer he keeps it open, the more difficult it will be to call it off.

He doesn't want the media to become so convinced that he is about to fire the starting gun that everyone is disappointed when he doesn't. It's a tricky problem.

With a bit of luck I should be able to start a whole new type of pointless speculation - what is the timetable and the method for calling the whole thing off?