Recently, in the United Kingdom, two issues have dominated the energy policy agenda: effective climate change mitigation and energy security. Whilst evolving government policy has led to government support for new build nuclear power as part of the nation's future energy mix, limited attention has been devoted to examining how arguments were constructed to lead ‘naturally’ to nuclear new build as an option for addressing these two issues. Using Critical Discourse Analysis this paper analyses the struggles within the climate change mitigation and energy security discourses in generating and/or replacing meanings. In particular, it examines how construction of the dominant (hegemonic) discourses led ‘naturally’ to the necessity of new build nuclear power. This paper draws upon 24 stakeholder interviews to examine the hegemonic and counter-hegemonic discourses. It outlines how climate change and energy security were perceived as motivators for energy policy; it shows how the combination of the dominant construction of climate change as an environmental issue and the construction of energy security as a ‘gas gap’ lent weight to the argument for nuclear new build. Struggling against these discourses is a counter-hegemonic discourse centred around climate change as a symptom of unsustainability and energy security as a lack of energy diversity. The latter, rather than ‘naturally’ proposing an urgent need for nuclear new build, lead to the argument for readdressing the focus of, and use of resources by, society – reducing energy demand and increasing energy supply diversity.