Introduction Cyber crime is a growing global problem. Despite intense efforts by law enforcement officers to stop the practice, cyber crime continues to spread. Brenner (2010) says that partly, the growth of cyber crime stems from the extra-territorial nature of the practice. On the contrary, Wall (2007) argues that the growth of cyber crime mainly stems from the changing nature of such crimes. The abuse of new technology has also led to the spread of this practice. Consequently, there have been rising numbers of cyber attacks in the United Kingdom (UK) and the United States (US). These countries have reported cyber crimes for many years and despite the increased attempts to curb their spread, they continue to increase. Loader (2012) reports that developed countries, which do not have an established internet connection also, report increased incidences of cyber crime. The American government has taken cyber security with utmost importance. In fact, the US Homeland Security considers America as a thriving ground for cyber crimes. This is because America is not only a victim of such attacks, but also the source of most attacks (Schell 2004). The Anti-Phishing Working Group recently produced new statics that show the growth of cyber crimes within the past year (Chik 2012). Increased awareness of cyber crime in the UK and America has largely informed the rise in the number of cyber crime litigation in both countries. However, most of these litigations do not have a common legislative basis. This paper explores the nature of cyber crime in the context of the law of defence (in the US and the UK). From this analysis, this paper highlights the legal underpinnings of UK and US laws on self-defence. A lot of emphasis is made to compare the application of the law of defence on cyber crime, viz-a-viz the application of the same laws in the “physical world.” In this regard, this paper explores the law of defence (as outlined by the UN), the right to bear arms, and the implications of these laws in the cyberspace. UK and US Laws on Cyber Crime America Since federal and state governments govern American states, the process of formulating laws divides between the state and federal governments. Usually, state laws are more applicable to cyber crime, unless there is a special situation where there is a need for Federal intervention (Chik 2012). For example, when cyber crime threatens national security, Federal cyber laws may apply. Alternatively, when the prevention of cyber crime requires the uniform application of law, the Federal government may intervene in the formulation (or enforcement) of such laws. Therefore, because of the distributed functions of state and federal governments, both governments have contributed in the formulation and enforcement of cyber law. Nonetheless, because of the political differences in America, every state formulates and enforces their laws. There is therefore no legal requirement for all American states to adopt uniform laws (Chik 2012). UK Specific legislations on cyber crime in Europe inform UK’s cyber laws. Indeed, there is a close relationship between Europe’s public policy on self-defence and UK’s legislations on the same. For example, the UK is subject to cyber crime legislations, as formulated by Council of Europe (CoE). Therefore, the