From June 2013, documents leaked by the National Security Agency (NSA) dissident Edward Snowden revealed that Western intelligence agencies are capable of bulk collection of electronic communications flowing through global telecommunication systems. Surveillance data shared by the “Five Eyes” eavesdropping agencies of the United States, United Kingdom, Canada, Australia and New Zealand include journalist’s communications. In the wake of the Snowden leak, Zygmunt Bauman and colleagues called for a systematic assessment of the scale, reach and character of contemporary surveillance practices. This paper explores a specific part of Bauman’s task by assessing the impact of the Snowden revelations on confidential source-based journalism. Interviews were conducted with a range of investigative journalists who have experience of covering national security in Five Eyes countries. All expressed serious concern over the intelligence agencies’ greatly enhanced capability to track journalists and to identify and neutralise their sources. The paper concludes that there is clear evidence of a paradigmatic shift in journalist–source relations as those interviewed regard Five Eyes mass surveillance as a most serious threat to the fourth estate model of journalism as practised in Western democratic countries.