MOST members of the SNP are over the age of 50 and not as socially liberal as “might be assumed”, experts have said.

While the race to become the party’s next leader will play out under the public gaze, only those who have already joined will have their say on who should succeed Nicola Sturgeon as first minister.

The SNP have become known for their progressive policies, but the membership is similar to others across the UK in terms of its makeup, according to Tim Bale, professor of politics at Queen Mary University London.

He said nearly three-quarters of members were thought to be in the ABC1 voter bracket – considered middle class – while less than 30% would be in the working-class grouping.

“As far as the SNP are concerned … in terms of their social class, they are much like other parties – it is very skewed towards middle-class membership,” he said.

“If you look at political participation generally, all the way through from voting to party membership to participation as MPs, politics is quite a middle-class sport in this country.

“That’s not to say there are no working-class people involved, but most will be middle class.

“Most of them will be men as well – again, that is pretty much par for the course with other parties as well. Men tend to join political parties more than women, so it is about 60% male, 40% female.”

Bale said the statistics were from a survey of SNP membership carried out just after the 2019 UK election, but there is likely to have been little change since.

According to that research, most members are in the 50 to 64-year-old age category at 40%, while 31% are over 65. In terms of younger members, 26% are aged 25 to 49, while just 3% are 18 to 24-year-olds.

“I think this is one that does always surprise people, although it shouldn’t because once again it’s par for the course for political parties – there is a big skew towards middle age and older,” Bale said.

“Around 70% of them are 50 or over, according to our figures.”

He added: “That is much in accordance with what you see in most political parties – in other words, party membership is not only a middle-class sport, it is a middle-aged sport, for the most part.

“And that, I think, does to some extent mean they are not as socially liberal as might be assumed because obviously older people do tend to have slightly more conventional, conservative views.

“That’s not to say they are socially conservative or illiberal, but they are not perhaps the social liberals that you might see in, for example, the Green Party. There would be a distinction there.”

Rob Johns, professor of politics at the University of Essex, said research which he carried out – which will be published in a new book – “exploded” some of the myths about the surge in SNP and Greens supporters after the 2014 referendum.

“A lot of people suggested the sudden influx of members was people who had been massively activist during the independence campaign and were really going to transform the parties,” he said.

“Whereas what we found is that actually there were just lots of people who were for independence, who were frustrated and thought, ‘this is something I can do’, but didn’t have much ambition to be active in the parties, and that is what happened.

“That is relevant to the leadership election, as sometimes people overstate the activist and impatient nature of the SNP membership and even their political interest.

“There are even people who joined the party twice as they had forgotten they had joined it – so a lot of those people won’t vote in the leadership election, a lot will vote but without having paid that much attention to what’s going on, let alone obsessing about the strategy for independence.

“And in that sense, there are more swing voters than we might expect, as members are not all as politically obsessive as we sometimes think.”

Johns also said the demographics of the SNP were “not distinct” from other parties in being mainly older, middle-class members.

He said there were similarities to Labour in the party having undergone a “liberalisation”, where socially conservative attitudes have been marginalised.

He said: “One of the weird things about leadership elections compared to normal voter elections, is it is not entirely clear what people should be voting for – whether they are voting for the policies they think should be enacted, the best leader for the job or some kind of combination of the two.

“I think they end up being more influenced by general impressions of candidates than they do necessarily by their policy profile.

“In Kate Forbes’s case, there’s plenty she thinks the membership would agree on, she is unfortunate in a sense that a great deal of attention is being paid to something that we don’t think voters in elections would be influenced primarily by – things like gay marriage – but they can form an image of somebody and that seems to be what is happening in this case.”

Johns said the response of members to these kind of criticisms would be varied – with some “really into politics”, while others would “absolutely be of a mind to ignore all that as froth”.

He added: “There is a definite danger this contest will fizzle out a little bit if there is a very overwhelmingly obvious frontrunner. And I think it will be interesting to see whether others can keep interest in this, and the more that happens, the closer the race will inevitably become.”