Curtice Says UK Two‑Party Test Toughest Since 1920s

Professor Sir John Curtice says opinion polls show the Conservative‑Labour duopoly facing its biggest challenge since the 1920s, with long‑standing records expected to tumble. Labour won a large parliamentary majority despite recording its lowest ever vote share for a governing party.

Recent local and devolved elections have shown a rise in support for smaller parties such as the Liberal Democrats, Reform UK, the Greens, Plaid Cymru and the SNP, while the two main parties have both struggled with low popularity. This fragmentation marks a shift from the postwar era when Conservatives and Labour captured about nine out of every ten votes, a pattern that has eroded as voters increasingly consider alternatives.

Curtice told The Times that the opinion polls suggest the traditional Conservative‑Labour duopoly is facing its biggest challenge since its advent in the 1920s, and that records are expected to tumble. He added that the old assumption that there is not enough room for a party to the right of the Conservatives or the left of Labour has vanished, making British politics fundamentally different from any postwar period.

Despite this, Labour secured a large parliamentary majority in the most recent general election, achieving it with the lowest ever vote share for a party that won an overall Commons majority.

The combination of a big seat majority with a modest vote share indicates that the electoral system is translating narrow support into outsized representation, raising questions about the durability of the two‑party model. Analysts suggest that if the trend continues, future elections could see even smaller vote shares producing governing majorities, or alternatively, a breakthrough by smaller parties that reshapes the composition of Parliament.

Watch for the upcoming local elections on Thursday, where shifts in vote share could signal whether the duopoly’s decline will accelerate or stabilize.