["Journal of Community &Applied Social Psychology, Volume 36, Issue 4, July/August 2026. ", "\nABSTRACT\nThe 2024 UK general election heralded the first change of government for 14 years. Based on social identity theory, we tested the IDEAS model to predict why supporters of different oppositional parties rejected the party in power. Previous tests of the IDEAS model had focused on attitudinal support and intentions for specific causes such as separatism, whereas the present study addressed its capacity to explain behaviour—voting for change—regardless of the (liberal‐conservative) orientation of the party that the voter supported. We predicted that the relationship between group identity, collective relative deprivation, collective efficacy and voting for change should be mediated by social change beliefs. Group identification and deprivation should also predict subjective well‐being. Unlike social change beliefs, well‐being should not mediate effects on voting. Using a preregistered survey of voters for the four main political parties prior to and following the election (N = 593), structural equation modelling supported most of the paths in the model. Social change beliefs mediated effects on voting intention as well as voting, whereas well‐being did not. The findings extend the scope of the IDEAS model to show why diverse sets of groups may pursue a shared objective of social change and bring about social and political transformations.\n"]