UKIP's share of the vote soared in May. The Conservatives' fell. Labour's fell more. What does that tell us?
Lord Ashcroft's polling tells us that a larger percentage of people supporting UKIP voted Conservative at the last election than voted Labour. (Indeed, we also know that a larger percentage of people supporting UKIP voted Tory than voted UKIP.)
And Survation's work tells us that until or unless UKIP's vote rises above 16 per cent, the party draws more from Conservative supporters than Labour ones. All in all, UKIP is more of a problem for David Cameron than Ed Miliband.
So how should we read the graph above, compiled by CCHQ after digging into May's local election results? A cursory glimpse might suggest that it is challenging the only conclusion that can reasonably be drawn from Lord Ashcroft's and Survation's work (and that of others).
After all, it shows the share of the vote won by "Others" - i.e: UKIP, mostly - rising by almost 20 per cent in a year, but that of the Conservatives' falling less than Labour. So UKIP is actually drawing more support nationally from Labour than the Conservatives, right?
Wrong. To draw such a conclusion would be to compare apples and pears. Local election results simply tell one what happened in local elections - which, remember, are never held across the nation as a whole. Local results aren't comparable to national results (or, indeed, national polls).
None the less, even though the graph isn't telling us anything much about what will happen at the next election, I think it is telling us something. Local elections are usually about protesting against the Government of the day.
And what the graph is telling us is not only that Labour, the official opposition, isn't scooping up that protest, but that its very nature is changing. The vote share of the two parties of government fell by roughly six per cent - but Labour's didn't rise by six per cent.
Instead, it actually fell by ten per cent or so. In short, CCHQ's research buttresses the view that local election protest is now aimed not so much against the Government of the day as the political class as a whole.
I asked CCHQ if by producing the graph above it was seeking to mislead those who read it into confusing apples and pears - in other words, into believing that UKIP is primarily a threat to Miliband rather than Cameron.
CCHQ deny this - saying that the point of disseminating the graph is to show that UKIP hits Labour as well as the Conservatives; that party members don't know this - and that they need to know.
I think that they know this perfectly well, and that this site's readers certainly do. But I may be wrong. Here, at any rate, are the figures and the graph. I've said what I make of them. You must make of them what you will.