Big Lib Dem recovery in latest ICM poll

A new ICM poll for the Guardian has topline figures of CON 37%, LAB 31%, LDEM 21%. Changes since the last poll are Conservatives minus 6, Labour minus 4, Liberal Democrats plus 6 (and by implication, the 'others' up four). From the last ICM Guardian poll, the changes are Conservatives minus 3, Labour minus 4, Lib Dems up 3.

This is a strange result and certainly doesn't tally with YouGov's finding yesterday, or what we'd really expect to find. It should come as no surprise that Labour are down, neither should we be shocked that the Liberal Democrats are up - the recent coverage of alleged negative campaigning by Chris Huhne might on first sight be a potential negative, but I suspect the Liberal Democrats main problem over recent months has been a lack of coverage full stop, so even this was probably good for them. Vince Cable's response to the missing benefit data affair also seems to have been well received, so I can quite imagine a big boost for them. The mystery is the significant drop in Conservative support, which has no obvious explanation.

There is a rule in market research called Twyman's law: "anything surprising or interesting is probably wrong". While not going that far, I would always advise that if you find a poll result that seems somewhat counter-intuitive, that seems to have no obvious explanation, treat it with caution until other polls support the findings. Statistically there is no more reason for this poll to be wrong than the last poll or the poll before that, and we may indeed find that this is a genuine trend and everyone starts showing the Tories down, but it is a bit odd.

It was only a couple of days ago that I was saying how the polls finally seemed to be presenting a consistent picture and now this comes along to upset it! Still, we have at least two timetabled polls due in the next week or two, plus whatever extra polls newspapers have commissioned on the back of the benefit data loss, so hopefully together they will give us a clearer picture.

UPDATE: It may be an even bigger recovery. Later reports in the Guardian have the Lib Dems on 23%...but report that as being three points up (which would put them on 21%, not 23%). No idea if they are actually on 21% or 23%.

UPDATE 2: Confirmed via Mike Smithson: it was indeed 21%.