Second World War: The Royal Navy submarine HMS Seraph began Operation Mincemeat to deceive Germany about the upcoming invasion of Sicily.

World War II or the Second World War was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were tried for war crimes.

The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against France. The modern Royal Navy traces its origins to the English Navy of the early 16th century; the oldest of the UK's armed services, it is consequently known as the Senior Service.

HMS Seraph was an S-class submarine built for the Royal Navy during the Second World War. Completed in 1942, she carried out multiple intelligence and special operations activities during World War II, the most notable of which was Operation Mincemeat.

Operation Mincemeat was a successful British deception operation of the Second World War to disguise the 1943 Allied invasion of Sicily. Two members of British intelligence obtained the body of Glyndwr Michael, a tramp who died from eating rat poison, dressed him as an officer of the Royal Marines and placed personal items on him identifying him as the fictitious Captain William Martin. Correspondence between two British generals that suggested that the Allies planned to invade Greece and Sardinia, with Sicily as merely the target of a feint, was also placed on the body.