We tend not to be too poll-obsessed here at LDV – of course we look at them, as do all other politico-geeks, but viewed in isolation no one poll will tell you very much beyond what you want to read into it. Looked at over a reasonable time-span and, if there are enough polls, you can see some trends.

Here, in chronological order, are the results of the eight polls conducted in November (hat-tip: Anthony Wells’ unrivalled UK Polling Report Blog):

Tories 40%, Labour 35%, Lib Dems 13% – Ipsos-MORI/The Sun (1st Nov)
Tories 36%, Labour 37%, Lib Dems 16% – Populus/Times (4th Nov)
Tories 43%, Labour 35%, Lib Dems 15% – ICM/Sunday Express (10th Nov)
Tories 41%, Labour 35%, Lib Dems 13% – YouGov/Sunday Times (16th Nov)
Tories 41%, Labour 32%, Lib Dems 14% – YouGov/Channel 4 (22nd Nov)
Tories 37%, Labour 31%, Lib Dems 21% – ICM/Guardian (22nd Nov)
Tories 40%, Labour 27%, Lib Dems 18% – ComRes/Independent (25th Nov)
Tories 43%, Labour 32%, Lib Dems 14% – YouGov/Telegraph (28th Nov)

Which gives us an average rating for the parties in November as follows (compared with October’s average):

Tories 40% (n/c), Labour 33% (-5%), Lib Dems 16% (+3%)

We haven’t yet got enough polling evidence to see whether Labour’s recent mini-nosedive following their well-publicised set of troubles – ‘Northern Rock-gate’, ‘Discgate’ and ‘Abrahams-gate’ – is a permanent feature, or a temporary blip.

The Tories appear not to have benefited much, if at all, from the Government’s woes, hovering around the 40% mark – pretty much where they’ve been since Gordon Brown flunked the election-that-never-was. The drop in Labour’s support seems either to have transferred to the Lib Dems or Others, rather than to the official opposition. Again, we’ll have to wait to see if David Cameron is able to capitalise sustainably on Labour’s misfortunes.

The Lib Dems have seen a partial recovery of fortunes, up 3% – though in reality this is more a correction to the extremely poor run of polls we endured in October at a time when the only media coverage the party gained was obsessed with Ming Campbell’s leadership. Since his resignation, the party has enjoyed more favourable publicity thanks to the efforts of Vince Cable, and the increased exposure of the leadership candidates in the mainstream media. Hopefully this can continue at least until Christmas, in the run-up to the announcement of the leadership result. After that, we will be dependent on early reactions to the performance of whoever is elected.

Finally, many poll-watchers have observed the disparity between Lib Dem ratings among the polling companies. Below are the Lib Dems’ average ratings in the last five polls for each of the six companies. You can see there is a marked difference – outside the margin of error – between YouGov (which consistently gives the Lib Dems their worst ratings) and ICM (which generally gives the party our best ratings) owing to their different methods:

YouGov = 13%
BPIX = 13%
IpsosMORI = 14%
Populus = 16%
ComRes = 16%
ICM = 17%

Which is probably why I give more credence to ICM…