It was in a diary that he kept while in prison in Paris that Sherwill gave the first indication that he had it in his mind to write a book. Faced with what he anticipated would be a very long term of imprisonment, in an entry dated 13th November, 1940, he wrote: "I think when I am really settled in, I will write a book on the German Occupation of the Bailiwick of Guernsey. Not a thriller but a fair and honest book..." Early in 1943, together with a large party of other islanders, he was deported from Guernsey to Ilag VII Laufen in Bavaria. Here he began to work on his book. However, on 29th June, 1943, some four and half months after his arrival, having been elected by his fellow internees, Sherwill "became pretty fully occupied as British Camp Senior for the rest of the 'duration' and so did not continue my literary activities." Ambrose Sherwill, by then Sir Ambrose, resumed writing his memoirs after retiring from the office of Bailiff of Guernsey in 1960.
