After the occupation of Latvia in 1940 the diplomatic service remained the only lawful representative of the state power of the Republic of Latvia. According to the extraordinary authority granted by the Cabinet of Ministers of the Republic of Latvia on 17 May 1940, Kārlis Zariņš, the Latvian ambassador in London became the head of the Latvian diplomatic service.

The diplomatic representatives of the Republic of Latvia who were accredited in a number of western countries started diplomatic combat against the USSR aggression already in July 1940 with the aim to safeguard the international status of the Latvian state, to protect the interests of their country and its citizens. This combat did not cease until the very restoration of the independence of the Latvian state.

The ambassadors of the Baltic states could continue work only in those residence countries whose governments permitted them to do so and continued to perceive them as duly authorised and subordinated to the jurisdiction of the last independent governments. A special role for the policy of non-recognition of the annexation of the Baltic states was that of the principal standing of the United States of America who refused to recognise inclusion of these states in the USSR either de iure or de facto.

During the period of refugee camps from 1944 to 1949 especially strenuous diplomatic activities were carried out by the holder of extraordinary authority Kārlis Zariņš, the Latvian ambassador in Great Britain, Alfrēds Bīlmanis, the ambassador in the USA, Jūlijs Feldmanis, the ambassador in Switzerland (from 1948 in the USA) (Switzerland prohibited operation of the embassies of the Baltic states in 1942, permitting J. Feldmanis to remain as a staff member).

The Latvian diplomatic representatives tried to explain the problems of Latvian refugees to the governments and the society of western countries and counteract the hostile USSR propaganda with regard to the former Latvian soldiers and refugees. Furthermore, ambassadors informed the central Latvian refugee organisations on the international events that affected the interests of Latvia and its citizens. As authorised representatives of the Latvian statehood the Latvian diplomatic representatives co-participated in the political and culture activities of the refugee community.