Ashcroft poll of Lib Dem marginals
Having polled Lab -v- Con seats last month, Lord Ashcroft has now done a similar exercise in ultra-marginal seats between the Liberal Democrats and Conservatives. He polled 17 seats. 6 are Conservative held seats where the Lib Dems came a close second last time and need not unduly delay us, all show a shift from Lib Dem to Conservative and Conservative holds, the most interesting ones being Watford (which was a three way marginal in 2010 and remains so in this poll) and the two Cornish seats in the sample which both put UKIP in second place, more on that later.
Turning to the Lib Dem seats polled, Lord Ashcroft did fieldwork in the ten most marginal Lib Dem seats with the Conservatives in second place. He also polled the special case of Eastleigh because of the by-election and UKIP, but we'll set that aside for now. The ten Lib Dem ultra-marginals represent seats with majorities of up to 6.4%, so they'd need a swing of 3.2% from LD to Con for the Tories to take them all at the next election. Based on national polling the Conservatives should do that easily (the national LD=>Con swing is about 5.5%), but as we know, Liberal Democrat MPs rely far more upon their personal support and tactical voting than MPs from other parties, and tend to be better able to confound a national swing.
Across the ten LD ultra-marginals the average swing from LD to Con was 3.4, so the Lib Dems continue to do far better in their own seats than in the country as a whole. However, "doing better" doesn't mean completely immune from loss. If that was repeated across all LD-Con marginals they'd still lose all those ten to the Tories plus perhaps Eastborne. In practice there is variation between seats, so some seats with smaller majorities the Lib Dems would cling on to, some more distant targets they'd probably lose. Looking at these particular seats Ashcroft found the Lib Dems doing far better than average in Sutton & Cheam, which this suggests they'd hold with ease, and better than average in Cheadle which this also suggests they'd hold. Those two are the most urban of the two seats polled - but with limited data points its difficult to tell if that's significant. North Cornwall's swing isn't far from the average, but would be too close to call.
If the Liberal Democrats lost only 10 or 11 seats at the next election they'd probably be quite pleased... but remember, the Lib Dems also have around 10 English seats where Labour is the challenger and 11 seats in Scotland that could be vulnerable to either Labour or the SNP, so this is not the only battleground for them. It's the largest Lib Dem battleground, but not the one where they are most vulnerable.
Two other things to note. Seats that have had a by-election are changed by it, so Eastleigh is probably representative of nothing but itself, but for the record Ashcroft found voting intentions there of CON 27%, LAB 10%, LDEM 39%, UKIP 22%. Also worth noting is how well UKIP are doing in the Cornish seats included here. Because it's a close LD v Con battleground Ashcroft's sample happened to include five of the six Cornish constituencies, and UKIP were running in second place in three of them. Take the UKIP scores with a slight pinch of salt because the timing of the fieldwork (it was mostly done during or in the fortnight following the European elections, so when UKIP were on a bit of a publicity high), but it's another potential pointer as to where they could do well.