Undercover Address – Post Office Box 506, Lisbon
Probably the least secret of all World War II undercover addresses was Post Office Box 506, Lisbon, Portugal, operated by the Thomas Cook & Son Ltd. travel agency of London. July 1940 press advertisements in Britain stated that mail service would be available to Belgium, Czechoslovakia, Danzig, Denmark, German-occupied France, Germany, Holland, Italy and Italian colonies, Luxembourg, Norway, German-occupied Poland, and the Channel Islands. The list was later expanded to include Bulgaria, Estonia, Finland, Greece, Hungary, Latvia, Lithuania, Romania, and Yugoslavia. The Cook firm collected a fee for the service, and mail handled through the system was subject to British censorship in both directions, but in a way that would not be revealed to the Axis countries’ postal authorities and censors.
Pictured Above and Below: A May 27, 1942, letter from Vichy France to the undercover address Box 506, Lisbon, with May 27, 1942, arrival backstamp, censored by Great Britain at London. An August 8, 1942, letter from Suno, Italy, to Box 506, Lisbon, censored by Italy at Milan and by Great Britain at London, remailed by Thomas Cook & Son Ltd. with address label pasted over Portuguese address.
The 2½-pence British stamp has the Thomas Cook firm’s TCS perforated initials.
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