How Britain Became a Disunited Kingdom in Five Charts

A public toilet with adverts for how to vote in local elections in Birmingham, UK.

Photographer: Chris Ratcliffe/Bloomberg

Local elections this week are expected to lay bare a new reality: the two-party system that has dominated British politics since World War II has broken down.

Polling ahead of the May 7 vote suggests the traditional Labour and Conservative duopoly is set to cede hundreds of council seats to populist rivals in a brutal demonstration of the challenges they face to reconnect with voters before the next general election.