Eventually he opens one containing a 'cunningly worded invitation to partake in World War II'. After some weeks similar letters arrive marked 'Urgent'. Milligan receives a letter marked O.H.M.S., which his uncle advises him not to open.

The family response is for Spike, his father and brother to produce boyish drawings of war machines (the drawings are included in the book), which are taken to the War Office. His mother is digging the air-raid shelter when Neville Chamberlain announces that Britain is at war with Germany. The prologue consists of only two sentences, which in itself represents the word-play humour that was Milligan's hallmark: 'After Puckoon I swore I would never write another novel.

The book was made into a film with the same title and adapted into a stage play. Milligan says in the preface: 'All the salient facts are true' at the end of the preface: 'There were the deaths of some of my friends, and therefore, no matter how funny I tried to make this book, that will always be at the back of my mind: but, were they alive today, they would have been the first to join in the laughter, and that laughter was, I'm sure, the key to victory.' The presentation is an unusual format freely mixing narrative anecdotes, contemporary photography, excerpts from diaries, letters, rough sketches and performance programs, along with comic sketches and absurd fake memoranda from ranking Nazi officials the hard facts are usually apparent. In Mussolini: His Part in My Downfall, having been stung by a critic who called the biographies unreliable, Milligan wrote, 'I wish the reader to know that he is not reading a tissue of lies and fancies, it all really happened.' The preface anticipates the book will be part of a trilogy years later, the cover of the fourth volume said: 'Don't be fooled this is the last, volume four of the war memoirs.' Ultimately, however, Milligan published seven volumes covering his war service, his first nervous breakdown and reallocation to rear-echelon duties, his demob and early years trying to break into the entertainment industry. The book spans the period from Britain's declaration of war on Germany to when Milligan lands in Algeria as a part of the Allied liberation of Africa.

Adolf Hitler: My Part in His Downfall, published in 1971, is the first volume of Spike Milligan's war memoirs.

My part in his downfall