EN
Mass surveillance is the most intrusive measure that security services are entitled to use in order to preserve public security. To ensure that use of these measures (e.g. wiretapping) is truly indispensable to maintain public order, the procedure of prior judicial review is established under Polish law. The role of the article is to analyse the theoretical background of such institutional and procedural solution, as well as to verify the practical aspects of mass surveillance on the basis of statistics received from the security services in Poland. The article constitutes also an overview of the main arguments presented before the Constitutional Tribunal during the hearing of the „surveillance case”, decided on 30th July 2014.