Who is switching to the Liberal Democrats?

So, we can be pretty confident now that there is a genuine surge in Lib Dems support. Apart from how long it lasts, and the affect on the narrative of the election, the other unknown is exactly who has shifted, and perhaps more importantly where. We will get a better idea of how things are moving when we get some polling of marginal seats, and when we get an updated version of YouGov's weighted regional breaks. In the meantime, we can draw some very tentative conclusions on the info we have so far.

If we compare the crossbreaks in the two post-debate YouGov polls so far with the averages of the crossbreaks in the three YouGov polls before the Lib Dem manifesto launch, and we compare the ComRes poll with the averages of the crossbreaks in their polls from before the debate, we can get some idea of which groups have swung the most. We need to remember that even combined together these are small sample sizes and they are not internally weighted, so at best this can only give us a broad brush idea of what is going on, but there are some consistent trends.

We can be fairly confident in saying that young people have swung the most strongly towards the Liberal Democrats. In both YouGov's post-debate polls they have had the Lib Dems in the 40s amongst under-35s, compared to the mid-20s prior to the debate, an average increase of 17 points. ComRes have a similar pattern. The Lib Dem boost amongst under 35s seems to be at least twice that amongst all older voters.

Secondly women may have swung to the Lib Dems more than men (more specifically, there's been a swing from Conservative to Lib Dem amongst both sexes, but Labour's vote has fallen much more amongst women). The contrast here is not as large as is it with age though, so I'm less confident this is a genuine pattern.

On social class there is no obvious pattern, YouGov seem to be showing a larger swing amongst C2DEs, but it is the other way round with ComRes. On regional breaks the evidence is also unclear, though both ComRes and YouGov seem to have the Lib Dems making the most progress in the North, and YouGov's figures are striking for the almost complete lack of a Lib Dem boost in Scotland. On other hand, late respondents to YouGov's new Scottish poll in the Scotland on Sunday today (whose fieldwork straddled the debate) did show swing towards the Lib Dems.