Depth of SNP support bucks a political trend that has held since the 1970s

One of the few predictions commanding widespread confidence in this election campaign is that, whatever the result on May 7, it will be a very good night for Nicola Sturgeon and the Scottish National Party.

The SNP is in an extremely strong position indeed. In late March and early April 2015, around 48% of Scottish voters intended to vote for the SNP. Labour, meanwhile, languished, with the other parties even further behind. As the graph below indicates, this is a major turn-around from the 2010 election, when Labour won comfortably in Scotland (indeed, this was the only part of the UK in which its vote share was higher in 2010 than in 2005).

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On these numbers, the SNP looks set to rout Labour in what is normally considered one of its heartlands. In 2010, 41 of Scotland’s 59 MPs were Labour, and just six were SNP. Now, however, the SNP could take a majority, perhaps even 50 or more, of Scotland’s seats, reducing Labour to a rump. What’s more, SNP membership has rocketed from around 25,000 in early 2013 to more than 100,000 now, with much of the rise occurring after the September 2014 independence referendum.

Hardly surprising, then, that the SNP surge has become one of the major stories of the election. But there is another story which is much less noted, though it is potentially even more important.

Something rather more fundamental is happening in Scotland. The country’s political landscape is being radically reshaped, potentially for the foreseeable future. To understand why, we need to look at another political trend: the long-term decline in the strength of voters’ allegiances to political parties (“partisan dealignment” in the jargon of electoral analysts).

The party’s over?

Partisanship (usually measured by asking people which, if any, party they generally identify with) is a voter’s long-term psychological attachment to a party. Although it influences how people vote, it is not the same thing. Individuals may have a long-term allegiance with a particular party, yet vote against it in a particular election, perhaps because of local tactical considerations, or for short-term reasons. But they will tend to return to their long-term allegiance over time.

Partisanship therefore acts like an anchor on voters’ choices. For the parties, partisanship is very important as it provides them with core support they can largely rely on. The more partisans a party has, the better its electoral prospects.

But the tide is running against partisanship. As the graph below shows, it is in long-term decline in Britain. In the 1960s, party loyalty ran deep. Around 85% of respondents to the British Election Study (BES) identified with a particular political party (the vast majority with either Labour or the Conservatives). And around 45% said they identified very strongly with that party. Only around 5% said they did not identify with any party.

The picture has changed dramatically since then. The proportion of people who said they identified very strongly with a political party declined steeply in the 1970s, and has continued to decline (albeit at a slower pace and with occasional small reverses) ever since.

By early 2015 (as revealed by the pre-election wave of the 2015 British Election Study) less than 20% of voters felt a very strong attachment with Labour, the Conservatives or the Liberal Democrats. And the percentage identifying with no party rose from 5% to around 19%.

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Over time, the percentage of the electorate that identifies with each party has fallen, albeit not steadily. In 1983, enthusiasm for the newly formed Liberal/SDP Alliance produced a brief increase in the proportion of the electorate identifying with those parties.

Similarly, in 1997, New Labour produced a temporary increase in the proportion of the electorate identifying with that party. But these short-term reversals notwithstanding, the long-term trend has been gradually downward: smaller percentages of the electorate identify with each of the established parties now than was the case in 1964.

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Accompanying this has been a more dramatic and pronounced decline in the percentage of voters who identify very strongly with the Conservatives, Labour and the Liberal Democrats. For each, this has roughly halved over the past 50 years. And it is worth noting that even in years when the overall proportion of partisans for a particular party went up (as in 1983 for the Lib/SDP Alliance or 1997 for New Labour), there was no matching recovery in the strength of its partisans’ attachment to their party: the new partisans had relatively shallow roots.

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This process seems inexorable. Voters are less intensely tied to particular parties than was the case in the past.

This matters, as it means parties can be less sure of the support of “their” voters. It also is a strong indicator of the major parties’ long-term problems. Voters are becoming more lukewarm about them as time goes on. Parties no longer excite intense enthusiasm or loyalty. It all feeds into a general picture of increasing public disengagement from the Westminster political mainstream.

Scotland bucks the trend

This trend continues in England, Wales and Northern Ireland. But something intriguing is happening to partisanship in Scotland. The following graphs show the story at every Holyrood and Westminster election since 1999.

For the main Westminster parties, the picture is much the same as in the rest of the UK: decline in the proportion of the electorate identifying with them. So far, so familiar.

But the SNP bucks the trend. The proportion of Scottish voters who see themselves as SNP partisans has generally grown. In 2011 there were for the first time more SNP than Labour partisans, and that remains the case in 2015. The SNP is not only the most popular vote choice in Scotland at the moment, but it has more partisans than any other party.

British Election Survey/Scottish Social Attitudes

This is important, as it suggests that the SNP’s vote lead is more than just an ephemeral feature of the current election. Something substantial has changed.

Will the SNP’s new partisans evaporate like the Liberal/SDP partisans in the late 1980s, or New Labour’s new partisans after 2001? Maybe. But there’s more. The SNP has bucked not only the trend for the number of partisans to decline, but also that for remaining partisans to become less strongly attached to their parties.

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Since the early 2000s, the proportion of Scots who see themselves as very strong SNP supporters has increased – slowly at first but with gathering speed, especially after the 2014 independence referendum. Now around 16% of Scots identify very strongly with the SNP. And more are “very strong” than are “fairly strong” SNP partisans (11% of Scots say this applies to them).

To put this in context, since the early 1970s, no other mainstream political party in Britain has enjoyed had such a high proportion of very strong partisans, or has had more “very strong” than “fairly strong” partisans. This is almost without precedent. The SNP really has changed the political weather in Scotland.

This dramatic rise in the proportion of very strong SNP identifiers does not guarantee that the growth in the party’s partisan base will be any more permanent than it was for the Liberal/SDP Alliance or New Labour. But it is something that neither the Alliance nor New Labour achieved, even at the height of their popularity.

This raises the distinct possibility that the SNP’s new position as the dominant force in Scottish politics will be long-lasting. Not only does the party have breadth of support – it also has depth. Its supporters are enthusiastic and mobilised, while its rivals’ supporters are declining and relatively lukewarm. The implications are far-reaching, both for the SNP and for the UK as a whole.

The SNP may have lost the referendum battle, but at the moment it seems to be winning the war for dominance in Scotland. And the dramatic rise in partisan support for the party suggests that dominance is likely to persist for quite some time to come.

Charles Pattie receives funding from the Economic and Social Research Council and British Academy