Labour are creeping slowly towards disaster in Scotland

On the face of it the latest Scottish polling contains some good news for the Labour party. According to a Survation poll for the Daily Record out today, the SNP's lead is gradually shrinking.

Two months ago, the SNP had a whopping lead of 24% over Labour. Today's poll cuts that lead down to just 17%.

However, the fact that Labour are taking comfort from being 'just' 17 points behind the SNP says all you need to know about the deep trouble the party are in north of the border. In any other circumstance, a poll showing that Labour are due to lose more than half of their Scottish MPs would cause outright panic in the party. That it is now causing mild relief, shows the scale of the difficulties Labour face to avoid total wipeout in Scotland.

While the changes in percentage terms may appear small, they can make a big difference in terms of seats. Analysis by polling expert John Curtice suggests that if Labour can get the SNP's lead down to just 10%, then they would hold on to around 20 of their 41 seats in Scotland. If on the other hand they can get the lead down to just five per cent then Labour could even emerge as the largest party.

That seems highly unlikely at this stage for two reasons. Firstly, there are less than three months to go until the general election and the current trend towards Labour is just too gradual. Secondly, the slight recovery in Labour's standing does not appear to be happening at the expense of the SNP. According to Survation, the SNP's share is down just one point from where it was in the immediate aftermath of the independence referendum. Labour may be recovering, but the SNP's support remains solid. In order to stand a chance of holding onto a majority of their seats, Labour need to take a big chunk of support back from the nationalists. So far that just isn't happening.

The root of the problem lies in Labour's message. Currently the core of their argument consists of warning Scottish voters that a vote for the SNP is a vote for David Cameron and the Tories. While this message has proven effective at previous general elections, all the signs are that it has lost it's potency. According to today's Survation poll a plurality of Scottish voters would rather see David Cameron as prime minister than Ed Miliband. SNP voters also narrowly prefer the Tory leader.

The SNP's argument that a vote for them would increase Scotland's voice in parliament also appears to be working. Among all Scottish voters a Labour/SNP coalition remains the overwhelming first choice, with 35% picking it as their preferred outcome over just 19% picking a majority Labour government. There is (predictably) even greater support for this among SNP voters, with 63% saying their preferred outcome is seeing the SNP in government with Labour.

Faced up against this, Labour's argument becomes very difficult. The argument that every seat Labour lose to the SNP makes it more likely the Tories will emerge as the largest party in Westminster is on the face of it quite persuasive. While there is no constitutional reason why this situation would automatically give the Tories the first chance to form a government, Labour's argument that it would inevitably do so in practice is probably true.

However, all the polls suggest that this argument is failing to work.

The reason for this is simple. While the argument that a vote for the SNP is a vote for a Tory government may hold some logical basis, it is basically a technical and mathematical argument. It is asking SNP supporters to look at the polls and calculate how best to keep one party they dislike out, while keeping a party they dislike less in.

It is basically a negative argument. It is asking voters not to back the party they really support, but to opt instead to make a calculation which would help a party they currently don't. Faced up against this technocratic argument, the SNP argument that a vote for them is a vote to increase Scotland's voice in Westminster is both simple and persuasive. It works on both a logical and an emotional level.

In a battle between a mathematical argument and an emotional argument, the mathematical argument will always lose.

For this reason it is vital to Labour's chances that they change their message to Scottish voters fast. If the Labour party are to stand any chance of holding on to their Scottish seats and therefore form the next government, they need to switch from a negative case to a positive one. Instead of urging voters to make a negative tactical vote against the Tories, they need to persuade them to make an active positive vote for Labour instead.

They need to persuade Scottish voters that a vote for Labour is something worthwhile in of itself, rather than just a means to keep the Tories out. This is a big ask. There are less than three months to go until the election and the collapse in Labour's vote in Scotland is something which has happened over the course of decades. However, it is clear that Labour's current argument is not enough to avoid disaster in Scotland. Jim Murphy and Labour must change their message fast. If they don't, their chances both north and south of the border look set to be over