Scottish Conservatives seize Aberdeen South in first by-election gain since 1967

Aberdeen South snapped back to the Scottish Conservatives on Thursday 18 June 2026, with Douglas Lumsden taking the seat on 14,308 votes and a majority of 6,050 over the SNP’s 8,258. The result marked the Conservatives’ first gain in a Westminster by-election in Scotland since 1967 and erased an SNP majority of more than 3,000 from the previous election.

The scale of the swing matters because Aberdeen South sits at the centre of Scotland’s energy debate. The Tory campaign leaned hard on North Sea oil and gas, arguing that voters were weighing the future of Aberdeen and the wider industry against the SNP’s stance on drilling and energy policy. Lumsden, already a Scottish Tory MSP, turned that message into a breakthrough in a seat the SNP had expected to defend with relative comfort.

The defeat is a clear setback for the SNP, which lost a Westminster constituency it had held after Stephen Flynn resigned his seat on 14 May 2026 following his election to the Scottish Parliament. Flynn’s move triggered the by-election under rules that stop politicians holding simultaneous Holyrood and Westminster seats. Aberdeen South had been one of the SNP’s more secure-looking urban targets, and the loss will sharpen scrutiny of how well the party can hold together its coalition in north-east Scotland.

Yet the wider picture is less straightforward than a single dramatic loss. On the same day, the SNP held Arbroath and Broughty Ferry, where Lara Bird was elected MP, while another Westminster by-election was taking place in Makerfield. That split result suggests Aberdeen South was not simply the start of a uniform national swing, but a seat where local economic anxieties and the energy question overrode the SNP’s previous advantage.

Labour’s fourth-place finish in Aberdeen South and Reform’s third-place showing also point to a fragmented opposition vote, rather than a clean transfer of anti-SNP support to one challenger. For the Scottish Conservatives, the victory gives Kemi Badenoch’s party a symbolic prize and a rare claim of momentum north of the border. For the SNP, it is a warning that even in a seat it had recently controlled, Aberdeen’s oil and gas politics can still reorder the map.