[1] Møller was elected as a Conservative member of the Folketing and in 1928 became leader of his party, a role he still held at the beginning of the Second World War.

However, his most important role in London proved to be as a broadcaster for BBC Radio's Danish language service aimed at occupied Denmark.

He spoke out against the Danish government's collaborative stance towards the Germans and encouraged sabotage and other resistance activities, becoming enormously popular as a result.

On 2 October 1943, an article by Christmas Møller appeared in Frit Danmark which urged all Danes to do what they could to help their Jewish fellow citizens who had gone into hiding from the Nazis' planned roundup.

In April 1945, Møller's son was killed in action while serving in the British Army's Grenadier Guards.