Snowden’s initial revelations aimed at establishing a public debate on online surveillance informed through the media. Media should serve the public’s need for information and offer various viewpoints and sources to enhance public debates. This study assesses how online surveillance is justified or countered in British broadcast news since the 2013 Snowden revelations for five selected major events in news coverage ending with the Charlie Hebdo aftermath in Paris in early 2015. The critical discourse analysis shows that UK broadcasts cover justification and delegitimation arguments of online surveillance. Online surveillance legitimation combines rationalisation (terror prevention) and moral evaluation (public security) arguments, which are often expressed by governmental actors. The broadcast discourse tends to give governmental, pro-surveillance actors a voice by default. The detailedness of terror threat descriptions increases over time. In 2013, ‘terrorist attacks’ are rather factually mentioned. In 2015, several ways leading to a loss of lives through terror are explicitly stated, which strengthens the instrumental rationality legitimation arguments. Delegitimising arguments predominantly use moralising and mythopoetic arguments (civil liberties) that are expressed by Snowden himself or politicians, yet rarely by non-governmental organisations, and very rarely by citizens. It is harder for non-governmental actors to continuously interpret the broadcast discourse. Therefore, what exactly is at stake when online mass surveillance increases remains obscure in the news discourse. The surveillance discourse should be richer in order to give the audience a chance to understand the vague and less tangible contra-surveillance arguments better.