Three UK parliamentary by-elections are being held on June 18, 2026, with particular attention focused on the contest in Makerfield, Greater Manchester. While seemingly local, the outcomes of these elections are considered potentially significant for national politics. Two of the by-elections are taking place in Scotland, but Makerfield is viewed as the key battleground. The results could be interpreted as a gauge of public opinion and a test of the leadership of Prime Minister Keir Starmer. A strong performance by the opposition could signal a shift in the national political landscape. The by-elections are being closely watched for indications of voter sentiment ahead of a potential general election.