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 18 polls published in September – the number is extra high this month because of the recently instituted daily YouGov tracker poll. (Note to self: we need to find a way of averaging the trackers, otherwise they will dominate and distort LDV’s (very unscientific) monthly poll average).

Tories 40%, Labour 27%, Lib Dems 18% – YouGov / D. Telegraph (7 Sept 2009)
Tories 40%, Labour 24%, Lib Dems 21% – ComRes / Ind. (8 Sept)
Tories 41%, Labour 27%, Lib Dems 17% – YouGov / S. Times (13 Sept)
Tories 41%, Labour 27%, Lib Dems 18% – Populus / Times (15 Sept)
Tories 43%, Labour 26%, Lib Dems 19% – ICM / Guardian (21 Sept)
Tories 39%, Labour 30%, Lib Dems 17% – YouGov / Sky (21 Sept)
Tories 39%, Labour 27%, Lib Dems 20% – YouGov / Sky (22 Sept)
Tories 38%, Labour 28%, Lib Dems 19% – YouGov / Sky (23 Sept)
Tories 38%, Labour 25%, Lib Dems 23% – YouGov / Sky (24 Sept)
Tories 40%, Labour 24%, Lib Dems 21% – YouGov / Sky (25 Sept)
Tories 39%, Labour 26%, Lib Dems 20% – YouGov / D. Telegraph (26 Sept)
Tories 40%, Labour 26%, Lib Dems 23% – ICM / News/World (27 Sept)
Tories 39%, Labour 29%, Lib Dems 20% – YouGov / Sky (28 Sept)
Tories 38%, Labour 23%, Lib Dems 23% – ComRes / Ind. (28 Sept)
Tories 36%, Labour 24%, Lib Dems 25% – Mori (unpublished, 28 Sept)
Tories 40%, Labour 29%, Lib Dems 18% – YouGov / Sky (29 Sept)
Tories 37%, Labour 30%, Lib Dems 21% – YouGov / Sky (30 Sept)

Which gives us an average rating for the parties in September as follows (compared with August’s averages):

Tories 39% (-3%), Labour 27% (+1%), Lib Dems 20% (+2%)

There’s a general caveat to all polls – which applies equally to all parties – published from mid-September to mid-October: it’s party conference season, and all the parties tend to receive polling spikes which coincide with their respective conferences thanks to the media coverage generated.

Even bad publicity tends still to work to their advantage; witness the post-conference polls for the Lib Dems. In spite of the media (and many Lib Dems’ private/public assessments) verdict that the conference was less-than-good, the party has enjoyed some of its highest poll ratings in years over the past week.

We will only be able to look at the polls again with some degree of confidence once the conference season is over, and ‘politics as usual’ returns. With that major caveat in place, let’s have a look at the figures from each of the main parties’ perspectives …

Tories: if they’re honest, they’ll be a bit unnerved to see their ratings dipping below 40% qute so regularly. Their ratings are likely to recover when their time for a bit of media attention arrives next week in Manchester, and I’d imagine, bar disasters, they’ll be back above 40% when I do the poll round-up for October. But, still, it shows the fragility of the Tories’ poll leads.

Feed this month’s LDV poll average into Anthony Wells’ UK Polling Report ‘swingometer’, and it projects a Tory majority of 24. Now, to be fair, that’s better than John Major achieved in 1992. But if that were the result, I suspect Tory activists would feel more disappointed than triumphant – and it would mean David Cameron was the captive of the more right-wing elements of his Parliamentary party.

Labour: well, it’s come to something when the Labour party can count a poll rating as a success if they hit 30%. They managed it on two occasions in September, but their average rating is still stuck just a notch above the mid-20%s. To put it in perspective, this is Labour’s eighth worst monthly average in the last 30 years – the other seven worst months were all on Gordon Brown’s watch as well, by the way.

There seems little doubt Labour is now stuck with Gordon, for better or, much more likely, worse. Quite simply, there’s no obvious alternative. It struck me this week: would the last 18 months’ leadership speculations have taken a different course if Robin Cook were still alive, and waiting in the wings?

Lib Dems: the party will be pleased – and, let’s face it, relieved – to have emerged from last week’s conference with such (relatively) strong poll ratings, topping 20% in our monthly average for the first time under Nick Clegg’s leadership. Indeed, it’s the strongest poll rating for the party since April 2006.

Lest this purely be written off as a conference-inspired fluke, it’s worth noting that this is the among the best September monthly poll averages for the party. Apart from the 2001-05 Parliament – which is skewed by the Iraq effect – this is the Lib Dems’ best September average poll rating apart from 1993, the lowest of low-points for John Major’s hapless Tory government. Of course, the question now is: can this be sustained, as the media focus moves back to the Labour party (this week) and the Tories (next week)?

The party leaders: if September counts as a good month for the party, it’s also a remarkably good month for the Lib Dem leader, with Nick receiving a stonking conference boost, over-taking David Cameron as the most popular party leader. YouGov has asked its ‘Do you think (name) is doing well or badly as (position)?’ question a number of times in September. Here are the results for the party leaders:

Nick Clegg: 44% (well) / 27% (badly), +17% – 13 Sept; 42% / 31%, +11% – 21 Sept; 54% / 21%, +33% – 25 Sept; 44% / 21%, +23% – 28 Sept.

Gordon Brown: 26% (well) / 70% (badly), -44% – 13 Sept; 28% / 68%, -40% – 21 Sept; 20% / 71%, -51% – 26 Sept; 29% / 66%, -37% – 28 Sept; 32% / 64%, -32% – 30 Sept.

David Cameron: 59% (well) / 31% (badly), +28% – 13 Sept; 52% / 32%, +20% – 26 Sept; 56% / 34%, +22% – 28 Sept.