By-Election Result: Aberdeen South

Not only were the Conservatives well in contention, but they won a stonking victory. They doubled their share of the vote, setting a new record for the seat and coming very close to an outright majority of votes cast. The SNP meanwhile slumped to their worst result since before the Independence referendum, a pretty dire result. I would say there are two key things to take away from this outcome.

Number one is how effectively the Conservatives were able to mobilise the anti-SNP vote. In 2024 they received 44% of the Pro-Union party vote; this time they acounted for 73% of the total in that camp. Consider we just last month had a proportional election, where you would expect votes to be more “genuine” than tactical, and across the area of this constituency the Conservatives will have landed in the low-to-mid-20%’s.

To earn over double that share the next month clearly requires tactical voting, the clarity and viability of which was enhanced by the closeness of the constituency result. To be clear, this isn’t a criticism or a de-legitimisation of the Conservative’s impressive victory here. This is how First Past the Post works, and they worked with exactly the strategy they needed to win in that scenario. That said, given the slip in SNP support, they didn’t actually need most of what they picked up.

Number two is that there’s very, very little we can actually infer from this result at the national level. The other by-election, in Arbroath and Broughty Ferry, was a comfortable SNP win. There are clear and obvious local circumstances relating to the future of the oil and gas industry, and part of the Conservatives’ successful vote mobilisation came from cleverly playing that card. The measures needed for the SNP to reverse this loss however may not necessarily help them elsewhere in the country, so from their perspective, caution rather than rash reaction would be wise.

At the risk of being extra cheeky, folk weighing up the inevitable contest to replace Swinney later this term might want to wonder what column “precipitates a by-election the party then lost” gets tallied into. Is it the same column as “obviously agitated for a show of strength over rather than gentle separation from Green Ministers, causing downfall of own First Minister”? What about “fumbles own selection announcement so badly they become the face of Holyrood legislating to require MPs to resign if they become MSPs”? What might these indicate about the political nous of the person inquestion? Positive things, I’m sure!

Anyway, moving down the results list, Reform barely saw any increase in their vote. Again, refer to last month’s Holyrood election: allowing for fact boundaries don’t perfectly align, they would have been on around 16-17% across this constituency. It’s very unlikely their support has halved since then, and so this is instead a clear indicator of that tactical rowing in behind the Conservatives.

Ahead of the vote, Labour were briefing they expected to lose their deposit. They managed to avoid that indignity by 0.4% of the vote, or just 105 raw votes. Nonetheless their share dropped by almost four-fifths, and that can’t all be ascribed to tactical incentives. Having won about 11-12% locally last month, they were already sitting on about half what they got in 2024. In other words of their loss in share (not necessarily raw votes), we can probably say two-thirds is down to their own loss of popularity, and a third to tactical voting.

Speaking of lost deposits, that was the fate for the other parties. The Lib Dems were a lot less negatively affected than Labour, but their support was still about half what they got last month which was about 8%. The SNP also failed to eat into the Green vote, as their share was barely changed versus 2024. It’s a third of the roughly 10% I reckon they’ll have got here last month, but by Green standards, at Westminster by-elections, under First Past the Post, it could have been a lot worse for them. The real local test for them will be the council by-election next week.