John Curtice: MEP vote may tell more than Fife

Every scrap of psephological evidence is being examined for possible pointers to what might happen in September.

The result probably tells us very little about where the referendum campaign is headed.

Yes, the SNP vote was down 13 points down on its vote locally in 2011.

However, incumbent governments, even relatively popular ones, nearly always lose ground in by-elections.

In the six previous Holyrood by-elections held since 1999 (excluding two fought in parallel with a UK general election) the vote of the senior party in government, be it Labour or SNP, fell on average by ten points.

Against that backdrop, the SNP performance in Cowdenbeath was a little disappointing but hardly catastrophic.

The party’s 28 per cent vote share still equalled its performance in the contest to which Cowdenbeath may provide some pointers, the European Parliament election in May.

In particular, the Liberal Democrats’ failure to stay ahead of Ukip affirmed the party’s dire standing and the potential challenge its faces in trying to hang on to its single Scottish seat.

To keep it, the party will almost undoubtedly have to stay ahead of Ukip – and indeed the Greens, who did not contest Cowdenbeath – in the Scotland-wide ballot.

On this performance, we cannot presume that it will succeed.

Meanwhile, the SNP’s somewhat disappointing performance – and Labour’s relatively strong 13 point advance to the 55 per cent it won locally in 1999 – is a reminder that recent polls have witnessed some closing of the SNP’s Holyrood poll lead.

At two points (according to YouGov), it is five points down on what it was in the run-up to the last European elections in 2009.

That suggests the SNP’s lead of eight points last time might be vulnerable – and losing in the spring would be much more of an embarrassment than losing Cowdenbeath in the depths of winter.

• John Curtice is professor of politics at Strathclyde University