The light at the end of the tunnel may not be an oncoming train.

Across a number of marginal seats, Survation, found that 46% of Tory voters and 37% of Labour voters would back the Lib Dems if their own candidate had little chance of winning.

So let’s take one such seat, East Dunbartonshire, where Jo Swinson (Lib Dem) is fighting the seat.

Let's do the arithmetic. In the latest Lord Ashcroft poll taken 17^th April, it suggested that the following would be the result. Then along comes Survation with their more recent poll. I've applied the Survation effect to the Lord Ashcroft poll and the results are very interesting.  No wonder the Lib Dems are throwing the kitchen sink at East Dunbartonshire.

Party                        Ashcroft Poll        Survation Applied

Conservative                12.00%                       6.48%
Labour                         16.00%                      10.08%
Liberal Democrat          29.00%                      40.44%
UKIP                           1.00%                          1.00%
SNP                            40.00%                      40.00%
Green                          1.00%                        1.00%

So assume the Tory and Labour voters do as the Survation poll suggests they might do, Jo Swinson would get an additional 11.44% of the vote, enough to give her the seat by 0.44%.  And it sure isn’t all over yet if you replicate that in other seats.  For example, across the Clyde in East Renfrewshire, Jim Murphy (Labour) may also benefit from the bounce with Lib Dem and Tories abandoning their party to get Jim Murphy back in. 

But there is nothing new in this in a sense, certainly in Scotland.  Tactical voting has been a factor in elections for decades given Scotland has had a four party system in full swing unlike south of the border where it’s been two party dominance.

So if one thing is sure, every vote counts in this election.