BBC, the voice of London

It was a major tool for our nationals to be informed during WW2. People used to listen it carefully, not to be detected by police informants. 
The photo shows the Portuguese section of the BBC, broadcasting from London.
Cortesão case is quoted as an evidence of Salazar attempt to intervene in the editorial line through the way the personnel was hired. From the abstract of Nelson Costa Ribeiro paper [read full text here]: «This article presents a case study on the limits of the BBC Overseas Service’s journalistic independence during World War II. Not only editorial policy but also the personnel hired by the BBC Portuguese Service were subject to pressure from Salazar through the Foreign Office. How the Lisbon government was made aware of the events taking place inside the Portuguese Service and which strategies were used to interfere in its editorial line are discussed. This history presents clear evidence of how the BBC was required to trim its output in order to avoid diplomatic problems arising between the British and the Portuguese governments.»
The book I wrote about Operation Longshanks in Marmagoa harbour shows how the station acted in that case as a tool of HM Government propaganda, not in order to inform about the true of the events but what could be useful in order to hide the act of piracy of the SOE station in Calcutta.
No one is innocent in the airwaves war.

Cerva: wolfram mine

Wolfram a vital mineral during WW2 and a tool for Portuguese neutrality through commerce with both parties.
The mine of Cerva at the North of Portugal {Vila Real] is now abandoned. But it was [see here, here and here for more] the source for tungsten and quartz. 
The mine was explored by Sociéte Civile d'Études de Tous Gisemants Miniers (Paris), after 1945 Companhia Portuguesa de Minas - Concessão de S. João de Escourêda; and after 1956 Minas de Cerva SARL.

Photo source: jab