By-Election Preview: Aberdeen South (UK Parliament) 18th of June 2026

Let’s make very clear, as was indicated above: Aberdeen South is not Aberdeen Deeside and North Kincardine. This is a substantially different seat to the one that Stephen Flynn won pretty narrowly last month, so the automatic assumption many are making that this will be on a knife edge needs a little bit of tempering. In relative terms swapping out that North Kincardine component for city centre areas is clearly to the SNP’s advantage. That said, what that may largely do is counterbalance the SNP’s losses to lower turnout and the more restrictive Westminster franchise.

In other words, by no means should the Conservatives be written off. The presence of the Greens will also gnaw on the SNP’s vote, with the George Street and Harbour area that goes to the polls again the following week being a particular hotspot. That’s within the Aberdeen Central constituency where the Greens actually placed second in the list vote, one of only two constituencies outside Glasgow and Edinburgh they ranked so highly. They will certainly see a lot of those voters going to the SNP on a tactical basis though, and the local party is still reeling from the chaos around the deselection and departure of their previous Aberdeen South candidate, Guy Ingerson.

If the Conservatives do pull off a win here, it’ll mean Douglas Lumsden going in the opposite direction to Stephen Flynn, giving up an MSP seat to become MP. It’d also give the party their only new blood in this term, bringing James Adams in via the list: as is entirely fair and proper, the Conservative voters of the North East Scotland region having voted for such representation. Conservative losses were so severe that their rump group was entirely composed of sitting MSPs, but Adams would be another newbie. Incidentally that’d also make Holyrood majority new MSP, as the election split it 65:64 in favour of returning MSPs!

Labour are conspicuous by their absence in my commentary thus far despite narrowly placing second in 2024, and that’s because they absolutely bombed last month. Although the Conservatives did worse in a Holyrood-to-Holyrood basis, they didn’t do all that much worse nationwide than they did in 2024. Labour on the other hand lost about half of their support. There’s absolutely no way they are in contention here, and indeed probably will have only won about 12-15% of the vote across the equivalent area at Holyrood.

A big question mark hangs over Reform voters. They did respectably in Aberdeen last month, but how tactical are their voters feeling? If they saw the SNP get run close at Holyrood, do they make the switch to the Conservatives to give them a bloody nose? Or are they so scunnered with established parties they don’t care? 

One last thing to note: relative availability of resources. The Conservatives ran the SNP close at an election in which the SNP were fighting hard across the whole country to hold onto seats, compared to a more limited Conservative spread of effort. Whilst the Conservatives will be able to concentrate all their resource on this single by-election, the SNP will be able to do likewise, seeing as the other by-election is far less competitive. 

Overall my instinct is that, especially when you consider a lot of the dissatisfied Labour vote might nonetheless still prefer the SNP to the Conservatives, the SNP go into this the narrow favourites. They are not so favoured for me to go for “Likely” winners, but certainly “Lean SNP” seems reasonable.