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 six polls conducted in December (hat-tip: Anthony Wells’ UK Polling Report Blog, which provides by far the best analysis of the polls on the web):

Tories 39%, Labour 34%, Lib Dems 18% – ICM/Guardian (19th Dec)
Tories 43%, Labour 31%, Lib Dems 16% – YouGov/Telegraph (19th Dec)
Tories 41%, Labour 30%, Lib Dems 16% – ComRes/Independent (16th Dec)
Tories 45%, Labour 32%, Lib Dems 14% – YouGov/Sunday Times (14th Dec)
Tories 40%, Labour 32%, Lib Dems 16% – Populus/Times (9th Dec)
Tories 42%, Labour 35%, Lib Dems 14% – Ipsos-MORI (7th Dec)

Which gives us an average rating for the parties in December as follows (compared with November’s average):
Tories 42% (+2%), Labour 32% (-1%), Lib Dems 16% (n/c)

Back in November, our poll round-up showed Labour plunging 5% following the debacle of the-election-that-never-was. It’s arguable Gordon Brown might be relieved that the bad press of the last month hasn’t resulted in an even sharper downturn than December’s 1% fall. What will concern Labour more is if the polls do not show any significant upturn in the coming few months, as May’s local elections approach. At the moment they seem locked in the 30-35% box where they were contained in the latter months of Tony Blair’s premiership. Six months after the Brown succession, and Labour’s back where they were.

The Tories have had a pretty good December. I commented last month – when the party was unchanged from October’s average of 40% – that “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 jury’s still out on whether Mr Cameron is building solid, election-winning foundations; but it would be churlish not to acknowledge that his party is gaining some momentum – albeit perhaps by default – in inverse proportion to the rate at which Labour is losing credibility.

The Lib Dems have stabilized since the nadir of October, when our poll average languished at 13%. In truth, we might have hoped to have done slightly better owing both to the fillip of Vince Cable’s impressive turn as acting leader, and the publicity surrounding the party leadership contest. Still, 16% is some kind of base for Nick Clegg to build upon, and does give the lie to those political commentators who still think that two-party politics is due some kind of pendulum-inevitable return. It isn’t. Two-party politics is dead.

Finally, as a Christmas treat, here are the previous December poll averages for the parties over the past decade:

1997: Labour 54%, Tories 25%, Lib Dems 16%
1998: Labour 53%, Tories 28%, Lib Dems 13%
1999: Labour 51%, Tories 29%, Lib Dems 15%
2000: Labour 46%, Tories 33%, Lib Dems 15%
2001: Labour 44%, Tories 29%, Lib Dems 20%
2002: Labour 39%, Tories 30%, Lib Dems 24%
2003: Labour 38%, Tories 32%, Lib Dems 22%
2004: Labour 38%, Tories 32%, Lib Dems 22%
2005: Labour 36%, Tories 37%, Lib Dems 19%
2006: Labour 33%, Tories 37%, Lib Dems 17%

It’s perhaps not the most cheering of trends to observe: our best December poll rating was five years ago, since when the trend has been down. That said, it’s also true that 16% is by no means our worst average poll rating in the last 10 years. In fact, 16% was our peak during Mr Blair’s first term of office.

So, no room for any complacency. But – equally – no reason for any political commentators worth their salt to write the Lib Dems off.