If this remains then CON majority chances are very slim

Dr Stephen Fisher has responded to the first wave of comments on his new GE2015 prediction model which suggests that the Tories have a 58% chance of a majority.

I think a key issue about the Fisher approach is the one featured in the chart above – 2010 LDs who’ve switched to LAB.

The scale of the LD>LAB switchers is huge. Currently it is greater than the cumulative increase in the CON vote from 1997 to 2010.

It’s not just me saying this about this segment. At a briefing session in September, organised by the Political Studies Association, Professor John Curtice described these voters as “Labour’s crutch”.

Curtice, who worked with Dr Fisher on the hugely accurate exit polls in 2005 and 2010, said they were important because so few CON voters at the last election have switched to LAB.

Given that the Lib Dems secured 24% of the GB vote at GE2010 the level of switching which has been broadly sustained across all pollsters since the first year of the coalition looks set to have a big impact.

In the massive 12,800 sample phone poll of 40 CON held key marginals from Lord Ashcroft last month there was a disproportionate sized shift from 2010 LDs to LAB in the key LAB-CON battlegrounds. This was part of the reason why the overall swing from CON to LAB in these seats was greater than in his separate national comparison poll taken at the same time.

I think that there is a good case to suggest that the high levels of CON to UKIP switching will decline as we get closer to the election. There is very little to indicate, however, that the 2010 LDs now acting as Labour’s crutch are slipping away.

If large numbers of 2010 Lib Dem voters stay with LAB it is very hard to see how the Tories can win a majority.

Mike Smithson