When and why do voters change their evaluation of party leaders? Voters’ evaluations of party leaders are an increasingly important determinant of electoral behaviour, but do apolitical factors like the personality of voters drive their evaluation of party leaders and therefore potentially endanger democratic accountability? Do voters evaluate party leaders with government office differently from opposition party leaders and do electoral campaigns change voters’ evaluations of party leaders? I employ a multilevel growth model with panel data from the United Kingdom to answer these questions. I find that the effect of voters’ personality is negligible while the effect of campaigns, voters’ ideology and stance on Brexit is considerable. Voters also differentiate between party leaders: party leaders who hold a government office are held accountable for bad economic performance, especially during election campaigns.