In 2013, Lee Rigby was murdered in Woolwich. In retaliation, there were several attacks on the Muslim community. Both series of events fall under the Terrorism Act 2000 legal definition of terrorism. Nonetheless, only Rigby's murder was treated as an act of terror by the government. This begs the question, as terrorism is defined in a broad and neutral way legally, what explains the selective use of the label of terrorism by the UK government? Answering this question begins by looking at terrorism from the perspective of Critical Terrorism Studies, approaching the label of terrorism as an act of securitization. As such, the thesis goes beyond the legal definition of terrorism, seeking to unearth the official policy narrative of terrorism on the UK. In order to do this, it analyses the three versions of Contest: The United Kingdom’s Strategy for Countering Terrorism, the government’s official terrorism policy papers. The analysis reveals an official policy narrative of terrorism which securitizes Islam, Muslims and Muslim identity, by constructing a causal story that places ideology and identity at the heart of the explanation for terrorism. Moreover, the concern with identity gives the narrative a strong nationalist characteristic. This is further deconstructed using the boundary-security nexus. The boundarysecurity nexus incorporates boundary and nationalism theory into securitization, which better helps to understand and explain how discursive constructions of security and identity work in a dialectic relationship. Once the nexus is introduced, it becomes clear how the selective use of the terrorism label by the government may not just further securitize Islam and the Muslim Community, but also act as a way of protecting and reinforcing the bounded community of the nation state.