PERHAPS it happened to someone you know, someone you love. Perhaps it happened to you. Perhaps it’s still happening. Whatever the case, the strange phenomenon of the people who joined the SNP (then left) is worth exploring because it’s the story of what all of us are going through.

You may remember how it started. There was the referendum in 2014 and some of us thought: “Well, that’s that then, let’s move on.” But the excitement felt by some of the Yes campaigners was not to be dampened down and fair enough: it morphed into rising support for the SNP and in particular rising membership. You probably saw the hashtags: #I’vejoinedtheSNP.

No one denied something real was happening. In 2010, the membership of the SNP was around 16,000, but by October 2014 it had reached 80,000. By the end of 2015 it was 115,000 and by the end of 2017, it was 118,000. There were no denials from the SNP press office then, believe me – quite the opposite. There were daily updates, daily boasts. Look how big we are!

To be fair to the party, no one could blame them for boasting: it was pretty remarkable stuff in the modern political landscape given membership of parties had come to be seen as something that was maybe a bit over and done with. Mass membership of Labour and the Tories was common until the war but it began to decline in the 1950s and 60s and never really recovered. To be honest, it was something for the oldies.

Then along came 2014 and I remember it well because people I know, including people in my family, were among those that joined up. Part of it seemed to be a desire to keep the momentum of Yes going, part of it (maybe the most Scottish part) was a kind of “screw you” to the unionists, and part of it was a genuine vote of confidence in the SNP. Whatever it was, the numbers rose.

And so now that, 10 years on, the membership is going the other way, what are we to make of it? Part of the problem, obviously, is that the SNP has been hoist by its own petard – they made a big song and dance about membership going up which means that others are making a big song and dance about membership going down which leaves lots of people doing songs and dances over something which really needs to be put into its proper context.

The thing is, impressive though the SNP numbers were, party membership has always been a small and rather over-blown part of the story. There’s no question that the wider Yes movement started to reach parts other campaigns couldn’t, particularly with young people, but the ones that actually joined the party were never really representative of the whole.

The figures, seen in research for the House of Commons Library, back this up. What they show is that membership of the SNP – like other parties – is not representative of the population generally. A particular type of person joins the SNP (and crucially now has the right to vote on the next First Minister) and the chances are they are not like the rest of us.

So, for a start, it’s generally older people who join up: in 2017, the average age of Tory members was 54, as it was in Labour. In the Lib Dems it was 51 while in the SNP, the members were 49 on average. One of the most remarkable aspects of the Yes campaign in 2014 was the way it seemed to engage a lot of young people, but they were not reflected in the membership in the way they were in the wider movement.

The same applies to class. The vast majority of the people who join parties are ABC1 and, perhaps unsurprisingly, it’s high in the Tories (83%) but it’s high as well in parties that are ostensibly progressive: Lib Dems (85%), Labour (77%) and SNP (71%). Again, this is a problem for the SNP in that it creates a disconnect between the wider support for Yes, which was particularly strong in working class communities and areas of deprivation, and the membership, which is, like the other parties, overwhelmingly bourgeois and middle class.

The other obvious factor to consider here is gender and once again it’s problematic. What the most recent figures show is that 57% of the SNP membership were men in 2017 and although that’s broadly similar to the levels in other parties, it also demonstrates that the membership is not reflective of the wider population. Obviously, the party has been led by a woman for the last eight years which may help, but there will be some women, particularly the ones that opposed the gender reforms, that would say the party has not been a woman-friendly atmosphere and the membership may reflect that, or cause it, or both, who knows.

The obvious next question is what effect the recent dramatic drop in membership – dismissed as drivel a few days ago before being confirmed as true – will have on the demographics of the membership. Possibly, the people that have left the SNP at the first sign of the bad times are the type that join things only in the good times, which leaves only the hard core as members. This may mean that the trends you see in the membership – mostly older, mostly middle class, and mostly men – will be exaggerated even more.

I wouldn’t mention any of this really were it not for the fact that this group that’s unrepresentative of Scotland, let alone the wider Yes movement, is in control. I was speaking to a bunch of young Yes supporters at an event the other day and, without exception, they were telling me they wouldn’t vote for the SNP if Kate Forbes was the leader. However, they were also pragmatic about the SNP being the only party that’s likely to deliver independence so who can say if they would stand by their antipathy to Forbes when it came to the crunch.

The point is that the voices of those young people aren’t widely represented in the membership that’s choosing the leader and it’s part of a bigger problem – for the SNP and for the rest of us. As far as the general population is concerned, it means a tiny part of the electorate – some 2.5% – is choosing the First Minister. But it’s also an issue for the SNP. It needs to find a leader that can create a movement that’s representative, big and growing. Problem is: its leader is being chosen by a group of people that’s unrepresentative, small, and shrinking.