This study employs archival research to produce a narrative of the early history of radio in Portugal, from its emergence through to the end of World War II. It analyzes foreign broadcasters' impact in the country during the War. The fact that Portugal was ruled by a dictatorship - the Estado Novo - meant that the country held great propaganda appeal for the Axis and Allied powers from very early on. Therefore, the main characteristics of the regime led by Oliveira Salazar were identified, with particular attention paid to its organization and communication policies. The Estado Novo's relationship with the media is the object of special focus since understanding of this is shown to be a determining factor in explaining the impact that foreign broadcasters had in Portugal between 1939 and 1945. Moreover, the main features of the propaganda policies implemented in Portugal by the warring nations - in which radio played a relevant role - are set out. The BBC's broadcasts, which began in June 1939, are analyzed in depth, since the BBC was the foreign broadcaster with the greatest impact in Portugal during World War II.
Besides covering the broadcasting content, this analysis also presents data on how such content was decoded in Portugal by the BBC's vast audience. Explanations for the great impact that the British radio station had on Portuguese listeners compared to other foreign stations that also broadcasted in Portuguese during the war are also provided. Lastly, this study examines the relations between the Voz de Londres [Voice of London] and the British and Portuguese political authorities. The British Government's interference in the editorial line of broadcasts to Portugal is demonstrated, and data proving how Salazar too was able to influence, to a certain extent, that editorial line is also presented.