The 2026 Aberdeen South by-election, scheduled for 18 June, follows SNP MP Stephen Flynn’s resignation after his election to Holyrood under Scotland’s dual-mandate rules. Trader pricing places SNP candidate Richard Gordon Thomson, a former MP for the neighboring Gordon constituency with local government experience and emphasis on the North Sea energy sector, at the head of the field. Douglas Lumsden of the Scottish Conservatives sits second, reflecting the seat’s recent electoral history as one of few remaining SNP Westminster holdings and the party’s rapid candidate selection. Other nominees, including Labour’s Nurul Hoque Ali and the Liberal Democrats’ Mel Sullivan, register minimal implied probabilities consistent with limited structural advantages in a short campaign dominated by energy policy and constituency representation.