Everyone in his family seemed to find war-work except DW. DW's stepson Bill Younger was already working for MI5, and his wife Joan secured a position as an MI5 driver. On the day war was declared even DW's old friend Joe Links turned up in an Air Force uniform - he had been put in charge of a barrage balloon section in Hampstead.
DW wrote several letters to the Ministry of Information offering his services as a writer and propagandist, but did not even receive the courtesy of a reply. In the early days of the war he even employed a viennese woman (Frieda Stottinger, or 'Fritzi' as she was nicknamed; she was in fact a british double agent, and DW employed her to provide her with cover as a favour to his friend Maxwell Knight in MI5) to trawl through the German newspapers in the British Museum looking for 'dirt' on the Nazi leaders, and when he offered this to the Ministry, again he received no reply.
DW asked his friend Maxwell Knight if he could find a niche for him too in MI5; but Knight was unable to oblige. He suggested that in order to keep up the public's morale he continue to write his thrillers. He also asked DW to house, and give cover as a researcher, to one of his agents, Fritzi Gartner, or 'Agent Gelatine', who was something of a beauty. According to one source, DW's stepson William Younger fell in love with her (he was neither the first nor the last) and proposed marriage to her, but his offer was declined.
DW worked on 'The Scarlet Impostor' at breakneck speed. Working most days from 10 a.m. until 2 a.m. the following morning he got it finished on 19th October. He had written one hundred and seventy two thousand words in seven weeks, and he considered it one of the best books he had ever written.
It was published in January 1940 and was a huge success - not least because DW had the innovative idea of giving it a contemporary setting, and sent his hero (Gregory Sallust) into war time Germany to wage secret battle there.
References : 'Stranger Than Fiction' Chapter 1.
'Drink and Ink' Chapters 16 & 17.
Phil Baker pp 387-392.
Craig Cabell Chapter 3.
Also, on Fritzi Gartner, Anthony Masters 'The Man Who Was M', pages 71-4 etc; and on Fritzi Gartner and William Younger, Bernard Connor, 'Agent Fifi and the Honeytrap Spies', Chapter Seven page 139.