1 Citizen-government collaboration on social media: the case of Twitter in the 2011 riots in England The final version is available from the Government Information Quarterly website: http://www.sciencedirect.com/science/article/pii/S0740624X14000847 Panos Panagiotopoulos a , Alinaghi Ziaee Bigdeli b , Steven Sams c a Brunel University London and Queen Mary University of London b Cass Business School, City University London c Brunel University London Email: P.Panagiotopoulos@qmul.ac.uk, Ali.Bigdeli.1@city.ac.uk Steven.Sams@brunel.ac.uk Abstract How social media can enable opportunities for collaboration between citizens and governments is an evolving issue in theory and practice. This paper examines the dynamic aspects of collaboration in the context of the 2011 riots in England. In August 2011, parts of London and other cities in England suffered from extensive disorder and even loss of human lives. Based on a dataset of 1746 posts by 81 local government Twitter accounts during or shortly after the riots, we explore how local authorities attempted to reduce the effects of the riots and support community recovery. Using Twitter's conversational and rapid update features, they produced a variety of informational and actionable messages with clear calls for offline or online action. In some cases, collective against the riots evolved in a mutual way: not only citizens were mobilized by local authorities, but also local authorities actively promoted actions initiated by citizens. Keywords: Public engagement, Collaboration, Social media, Twitter, England riots, UK local government, Online research methods.