The evidence suggests that it’s working the other way round
It’s been repeated often enough on PB that an essential part of Labour’s polling position is based on the very large proportion of 2010 LD voters who’ve now switched to Labour. If this hadn’t happened or starts to slip away then EdM’s dreams of becoming PM are in trouble.
So far, at least, the evidence is that such a move that is even more pronounced in the key LAB-CON marginals that the Tories have to hold to prevent a LAB government.
The other side of the equation is that in the LD-CON marginals there’ll be a collapse in the LD vote which will help the Tories secure the easy pickings that will boost their seat totals. This was seen earlier in the week I featured a projection from Martin Baxter’s Electoral Calculus on the projected seat outcome with CON 35: LAB 35: LD 12: UKIP 10 and Miliband’s party were 5 seats short of a majority. Amongst the changes were 18 CON gains from the yellows.
But there’s strong evidence from the most recent marginals polling that we have is the LDs would do much better. That was published by Lord Ashcroft in September and, clearly, it could have take a knock by recent events. But if “Rennardgate” works out like “Falkirkgate” and “Plebgate” the effect could ease off in the days and weeks ahead.
The chart above based on that data suggests a LD>CON swing of just 0.5% in seats that the blues will be defending against the yellows. If that was translated to seats that the LDs are defnding against the Tories it would lead to just two changing hands.
At the moment the LD collapse is underpinning Labour but not offering much to the Tories. That could make the blue GE2015 challenge even harder.