Opinion Polls, Turnout and the Demand for Safe Seats

Do opinion polls sway turnout and shape political competition in majoritarian systems? Can they strengthen the persistence of safe seats? Analysing national opinion polls during UK general elections and the perceived safeness of constituencies, we find that pre-election polls significantly affect voter turnout. Non-competitive elections predicted by national polls suppress turnout, especially in areas with low perceived electoral competition. This reinforces the advantage of trailing parties in their strongholds, potentially fuelling party demand for safe seats that may give rise to demands for gerrymandering. This can exacerbate spatial polarization of the electoral landscape, with implications for governance regarding opinion polling.