In the context of the proliferation of extremist hate speech in Europe in recent years, legislative provisions have been enacted that inevitably resulted in potentially substantial limitations on the right to freedom of speech. A number of individuals have been subjected to onerous administrative measures in relation to their speech – sometimes after a criminal conviction, sometimes in the absence of criminal law action. Thus, the question of proportionality has inevitably arisen – to what extent can a state legitimately and justifiably restrict the right to freedom of expression in the interests of national security? To put it differently, in respecting its broader social obligation to ensure and preserve security, how much should a state qualify the right to freedom of expression? In addressing these questions, this comparative report will first outline in more detail the applicable international and regional legal obligations and relevant case law in Sections 1 and 2 respectively. Section 3 will focus on the following countries – Belgium, Denmark, Germany, France and the United Kingdom – with particular emphasis on domestic legislative provisions, jurisprudence and national strategies specifically adopted to respond to the risks posed by extreme speakers. It should be noted at the outset that the United Kingdom has legislated against extreme and radical speech within its counter-terrorism legislation. The report will conclude a list of conclusions and closing remarks based on the impact of these domestic practices and legal responses on the right to freedom of expression.