This paper attempts to advance the study of microblogging and political events by investigating how one particular high profile programme acted as a stimulus to real-time commentary from viewers using Twitter. Our case study is a controversial, high-ratings episode of BBC Question Time, the weekly British political debate show, broadcast in October 2009, in which Nick Griffin, leader of the far right British National Party, appeared as a panelist. The ‘Viewertariat’ that emerges around a political event such as this broadcast affords the opportunity to explore interaction across media formats. The paper contains our first efforts to understand this relationship. In order to do this, we gathered 43,730 tweets and analysed them to learn the extent to which this content was structured through the use of addressed tweets, hashtags and retweets, and the distribution of comments among both users and over time. We then narrow our focus to understand a specific segment of the programme, focusing on a period around 23:20, the point in time where the Viewertariat is most verbose. We argue that this example demonstrates a fluid ‘structure of participation’ in which the Viewertariat responded to the broadcast in various ways. This raises several questions for further research and offers the potential for great methodological innovation, an issue we consider in the conclusion of this paper. The full text of the paper may be downloaded from the UEA working paper series website.