The support for ‘Yes’ in some Labour heartlands, together with the recent success of the SNP, Scottish Greens and SSP in attracting new members has created some exited speculation about the 2015 UK Parliament seeing a collapse in Labour’s Scottish representation at Westminster. For example Kevin McKenna argued in today’s Observer that “Ed Miliband will require all of his 41 Scottish Labour MPs to be returned if he is to have any hope of winning an overall majority at Westminster next year. Yet how many of them would survive a backlash from among the 1.6 million who voted yes and who have effectively renounced the Labour faith?”

So how many would survive?

A Survation opinion poll taken after the referendum shows a major swing to the SNP – going from the 20% it got in the 2010 to 35%, which is a 75% increase it the vote. However the Labour vote is largely unchanged, only down a couple of percent on 2010. The real losers are the Lib Dems, who,it should be remembered were the second biggest party in the 2005 General Election in Scotland, and level pegging with SNP in the 2010 General Election, but who are apparently on only 3% now.

That is why if you plug the figures into the UK Polling Report website’s swingometer it shows that while this increase in SNP vote is predicted to lead to an increase in SNP seats (in this case from 6 to 14) it is likely to mainly come from the Lib Dems. Only Falkirk sees a Labour loss – even Dundee West would stay Labour on a uniform swing. That is because the scale of the existing Labour majorities is so huge that it would take an unprecedented swing to see Labour not win. Where Labour already get more than 50% of the votes, even if the SNP take every non-Labour vote they can’t win. Only when the Labour vote slips behind the SNP vote does the swingometer turn west central Scotland from red to yellow.

What is particularly interesting is the comparison between the tables for Westminster votes and Scottish Parliament votes. While only 35% of those surveyed said that they would vote SNP at Westminster, fully 49% of the same group said they would vote SNP for Holyrood. Some it appears that the split vote may be a very conscious choice. The survey also had an incredibly high number of undecided voters, so it is questionable how accurate a representation of reality it is. However it does show that even a remarkable SNP performance, which is what a 35% vote share would be, will not guarantee a decisive shift in representation (unless there is a dramatic shift in vote distribution across the country, but even the tiny Glasgow subsample still shows Labour leading for Holyrood 55% to 39%).

Rumours of Scottish Labour’s imminent Westminster demise therefore seem exaggerated..