Are changes in citizens' attitudes towards EU-integration endogenous to populist campaigns by tabloid media outlets? The question to what extent public opinion is a consequence, rather than a cause of media reports is difficult to answer because citizens self-select into media consumption. We use a unique quasi-experiment in the United Kingdom -- the boycott of the most important rightwing tabloid newspaper, the Sun, in the Merseyside region as a direct consequence of the Sun's reporting about the 1989 Hillsborough soccer disaster -- to identify the effects of reading the Sun on attitudes towards leaving the EU. Using a difference-in-differences design based on yearly British Social Attitudes data spanning the years from 1983 to 1996, we show that this specific event caused a sharp drop in Sun readership in Merseyside. We also show that respondents' attitudes towards the EU got significanty more positive in Merseyside after the boycott, compared to attitudes of respondents in other Northern cities. We estimate this effect to amount to around 10 percentage-points. The results of this paper have important implications for our understanding of media effects and suggest that the tabloid media played a key role in influencing attitudes towards the EU.
