A week after writing 'The Invasion and Conquest of Britain', DW produced a supplement to his first paper called 'Further Measures for Resistance to Invasion', and while the Battle of Britain raged, he wrote three papers on 'Village Defence' in which he detailed ways in which ordinary Britons could fight the Nazis inch-by-inch in bloody local skirmishes if the Germans did manage to gain a foothold on British soil.
Perhaps his most interesting paper of this period is his seventh, 'A New Gibraltar', written on 15/17 July 1940.
Not realising how weak the Country really was, the public were clamouring for the armed forces to fight back, and DW was asked for his thoughts on how this could be done without staging what would be a suicide mission to no avail.
DW's answer was an invasion of Sardinia.
He returned to this theme a year later, in his War Paper No. 19 (of 12/15 July 1941) called 'While The Cat's Away'. Initially DW envisaged it as a way of keeping up public morale, but later he developed the concept further, suggesting Sardinia should be used as the springboard into Italy rather than Sicily, and as a base from which to conduct bombing raids against a large number of German held territories.
This idea of occupying Sardinia was to crop up again later in DW's wartime career at the Casablanca Conference in January 1943. Various notables including Montbatten and the Commander-in-Chief of the Mediterranean Fleet, Admiral Sir Andrew Cunningham supported the concept, but they were bitterly opposed by Alan Brooke and the Americans, and the latter won the day.
DW was to hold in later life that the decision to go into Sicily rather than Sardinia was one of the biggest blunders of the war.
Below the images from DW's Sardinia papers can be seen the opening pages of DW's Paper No. 9, 'This Winter', concerning the challenges that the winter of 1940 might pose to the war effort. Written before the blitz between 5th and 7th August 1940, DW thought the paper long lost - even he did not have access to a copy when he wrote 'Stranger than Fiction' in 1959. This copy was re-discovered among DW's papers late in 2018.
References :
'Stranger Than Fiction' Chapters 3 - 12.
'Drink and Ink' Chapters 19 - 22.
Phil Baker pp 402 - 410.
Craig Cabell p12 Chapters 7 & 12.
Tina Rosenberg Chapter 3