The smallest number of given squares in a sudoku that can produce just one solution is 17 The best pop single is “But I’m Different Now” by The Jam But there is one question that this column cannot answer. That is: how would voters react to a head-to-head contest between Gordon Brown and David Cameron?

This might seem something of a problem for a political column. On the contrary, it is an opportunity, because the reasons why it is so difficult to answer are so intriguing, especially after a week in which Cameron stumbled over tax’n’spend – the central issue of British politics since the dawn of time. Who knows whether, if Brown is installed as prime minister, people will regard his experience as trumped by Cameron’s personable manner? Opinion polls tell us many things, such as that Brown’s record of delivering economic stability is hugely respected, and that Cameron’s appeal runs far ahead of that of his party. But they are imperfect guides to the future because, as John Curtice, the professor of polling wisdom, says, “people are rather bad at predicting their own behaviour”.
Certainly, Cameron’s strategy and poise have so far been exemplary.

Which only makes the embarrassment of last week’s Tory tax report the more puzzling We know what happened. A junior person put it on the Tory party website a day early by mistake. A senior person at Labour HQ noticed and alerted Gordon Brown’s office. Ed Balls, the Economic Secretary to the Treasury, was soon on all available media outlets condemning Tory plans to cut public spending by £21bn a year. Incidentally, that shows how fast and focused the Brown/ Labour machine is, at a time when the Blair/Labour apparatus is looking a bit ragged. But the main point is that David Cameron and his shadow chancellor, George Osborne, seemed nonplussed and defensive.They both repeated that they would not be promising “upfront” tax cuts Which implied that there might be some tax cuts “down back”. Down the back of what: Gordon Brown’s sofa? It has been speculated (by me, among others) that Cameron was looking for a fight with the tax-cutting wing of his own party in order to dramatise the change wrought by his leadership If so, this wasn’t it.

The impression given was of a pair of small-state Conservatives caught in their dressing room putting on their “Party of the NHS” outfits.We can see why the report was awkward for them: the tax commission chaired by Lord Forsyth was appointed by Osborne a year ago, when Michael Howard was still Tory leader. Since then, the political world has been turned upside down by Osborne’s friend Cameron, and Osborne’s flirtation with flat taxes (that is, tax cuts for the rich) looks very last year. Flat taxes are right off the script written by Cameron’s other best friend, Steve Hilton, the ideologue of the kinder, gentler Conservatism that is now the core message. The most telling sentence in the Forsyth report was the one saying that environmental taxes were “beyond its remit”.But that does not explain why its accidental early publication should have wrong-footed Cameron.

Surely he and Osborne had already decided how to deal with it? Or are there hints here of tension between the two; early signs of Blair-Brown syndrome?One-nil to Brown, anyway, in the unfriendly match that is the warm-up for the main event. Although it is worth remembering that Brown has not yet formally come through the qualifying stages to guarantee his place in the final. Statistically, there is still a chance that Alan Johnson could run against the Chancellor and win. As Labour MPs returned to Westminster this month, I was told that there are “50 to 60 who are Anybody But Brown”, but most of them are hiding in the maquis, waiting and seeing. I am also told that the line peddled by Nick Brown, the Chancellor’s unofficial chief whip, has been mildly counter-productive. He has been canvassing MPs, telling them that “the door is closing” if they want to get into the I’m Backing Gordon government job centre.Nevertheless, the Chancellor is close to carrying all before him.

Another Labour MP summed up the mainstream view to me thus: “Gordon is like a hurricane far out to sea. No one knows where it will hit, or how many roofs will be ripped off, or if we will all get through it. But we know it’s coming.”Brown as prime minister remains a great whirling unknown at the centre of politics. The four are accused of illegally taking control of $10bn (£5.3bn) of the company’s assets.
The first Osborne, 55, heard of the accusations was when a reporter rang him.