British journalist of Australian heritage and, during World War II, a propagandist for the British government. Fluent in German, he became friendly with Ernst Röhm who arranged for him to interview Adolf Hitler in April 1931. During hostilities he led a black propaganda campaign against Hitler by radio from England, so successfully that he was named in the Nazis’ Black Book for immediate arrest after their planned invasion of Britain.
His father, Frederick Sefton Delmer, a Jew, born in Hobart, Tasmania, was Professor of English Literature at Berlin University and author of a standard textbook for German schools. At the outbreak of the First World War his father was interned in Ruhleben internment camp as an enemy alien. In 1917, the Delmer family was repatriated to England in a prisoner exchange between the British and German governments.
After leaving university, Delmer worked as a freelance journalist until he was recruited by the Daily Express to become head of its new Berlin Bureau.
In the 1932 German federal election, Delmer travelled with Hitler aboard his private aircraft. He was also present in 1933 when Hitler inspected the aftermath of the Reichstag fire. During this period, Delmer was criticised for being a Nazi sympathiser, and for a time, the British government thought he was in the pay of the Nazis. At the same time, the Nazi leaders were convinced Delmer was a member of MI6; his denials of any involvement only served to strengthen their belief that he was not only a member, but an important one.
In 1933, Delmer was sent to France as head of the Daily Express Paris Bureau. In 1936, Delmer married Isabel Nichols. Delmer covered important events in Europe including the Spanish Civil War and the invasion of Poland by the Wehrmacht in 1939.
Delmer returned to Britain and worked for a time as an announcer for the German service of the BBC. After Hitler broadcast a speech from the Reichstag offering peace terms, Delmer responded immediately, stating that the British cast the terms in “your lying, stinking teeth”.
In September 1940, Delmer was recruited by the Political Warfare Executive (PWE) to organise black propaganda broadcasts to Nazi Germany as part of a psychological warfare campaign. Delmer also oversaw the production of a daily “grey” German-language newspaper titled Nachrichten für die Truppe (“News for the Troops”), which first appeared in May 1944.
After the Second World War, Delmer returned to the Daily Express as chief foreign affairs reporter, and over the next fifteen years, he covered nearly every major foreign news story for the newspaper.
Delmer wrote two volumes of autobiography, Trail Sinister (1961) and Black Boomerang (1962), and several other books, including Weimar Germany (1972) and The Counterfeit Spy (1971). He died on 4 September 1979 at age 75.

Link to Wikipedia biography