[1] Upon the coming of peacetime Purchase continued his career pathway and resumed his interrupted legal and medical studies, becoming a barrister in the Inner Temple in 1919 and a Bachelor in Medicine in 1921.
His jurisdiction shifted over different neighbourhoods within London, but always included the broad area of dense population from the City of Westminster on the southwest to Islington toward the northeast.
In cases where the cause of death was unknown or where inquiries were required to assist the police, Purchase worked closely with specialists in forensic pathology such as Bernard Spilsbury and Keith Simpson.
The World War II special operation centred on the release in Spanish territorial waters of a body dressed in the uniform of a British marine officer-courier.
As a counter-intelligence initiative, the operation pointed German military intelligence, the Abwehr, toward locations far away from the Allies' true target of Sicily.
The German armed forces did not take steps to establish tactical air command over Sicily at the time of the Allies' amphibious assault, and Operation Mincemeat is said to have saved thousands of lives.