This is the main driver of the bigger CON to LAB swing in the marginals

I was on a train heading to London to speak at a conference when Lord Ashcroft’s latest CON-LAB battleground polling was published yesterday and have only now got round to looking at the detail.

The most striking feature and a big driver of Labour’s strength in the seats polled is how well the party is doing in attracting and retaining 2010 LD to LAB switchers. What’s even more marked is that the levels of switching appear to be substantially greater in the single constituency polls than in Lord Ashcroft’s national surveys.

I looked at the proportion of switchers in the last four Ashcroft National polls and compared them with the average level of switching in this latest round of marginals’ polling.

The positive feature for the Conservatives in all of this is that in the CON-LAB marginals there were fewer LD voters than in the country as a whole. So the greater propensity to switch covers a smaller segment of the electorate.

The level of switching, however, more than compensates for this.

All polls are snapshots and this might not continue until May 7th. On the other hand the still large number of 2010 LD voters yet to make up their minds are likely to come into play.

We are promised much more from Lord A in the weeks that remain and I will continue to track this.

Lord Ashcroft’s English polling could have a similar level of bad news for the Tories in England as his surveys North of the have for Labour.

Mike Smithson

For 11 years viewing politics from OUTSIDE the Westminster bubble

For latest polling and political betting news follow @MSmithsonPB