Abstract: Previous research suggests media attention may cause support for populist right-wing parties, but extant evidence is mixed and mostly limited to proportional representation systems in which such an effect would be most likely. At the same time, in the United Kingdom's first-past-the-post system, an ongoing political and regulatory debate revolves around whether the media give disproportionate coverage to the populist right-wing UK Independence Party (UKIP). We use a mixed-methods approach to investigate the causal dynamics of UKIP support and media coverage as an especially valuable case. Vector autoregression (VAR) using monthly, aggregate time-series data from January 2004 to February 2016 provides new evidence consistent with a model in which media coverage drives party support, but party support does not drive media coverage. Additionally, we identify and explore two key periods in which stagnating or declining support for UKIP is followed by increases in media coverage and subsequent increases in public support. Overall the findings show that media coverage may drive public support for right-wing populist parties, in a substantively non-trivial fashion irreducible to previous levels of public support, even in a national institutional environment least supportive of such an effect. The findings have direct and troubling implications for contemporary political and regulatory debates in the United Kingdom and potentially liberal democracies more generally.