Operation Sea Lion: Hitler’s Cancelled Invasion of Britain

Warfare History Network

History, Europe

The planned 1940 invasion of Britain, Operation Sea Lion, remains one of the great “what-ifs” of modern military history.

Major Graf Von Kielmansegg, an officer in Germany’s  1st Armored Division based near Orleans, France, was dragged from a cinema on the night of August 28, 1940, and told to report to his chief of staff. “As I entered his office I was sure that we were finally going to be told that Sea Lion had been given the green light. I asked, ‘Are we on our way?’ He said, ‘Yes, we’re on our way but not to England, to East Prussia.’ So then we knew Sea Lion was a dead duck.”

Von Kielmansegg was right. German Führer Adolf Hitler had decided instead to proceed with Operation Barbarossa, the invasion of Russia, which had killed Sea Lion.

Summer 1940 has obtained something of a mythical quality among the British. Many felt at the time that the Germans merely had to turn up on the shores of Britain to defeat the nation. The average citizen knew little, only what he saw, for example, the antics of members of the home guard parading with broom handles or newsreels depicting a defeated army—having lost all its heavy equipment—being rescued from the beaches by little ships off Dunkirk.

However, on the other side of the hill at Dunkirk, the Germans were as confused in victory as Britain was in defeat.

On July 16, Adolf Hitler, in his role as dictator of Germany and supreme commander of its armed forces, issued his Directive No. 16, in which he stated, “As England, in spite of the hopelessness of her military position, has so far shown herself unwilling to come to any compromise, I have decided to begin to prepare for, and if necessary to carry out, an invasion of England.”

A Confident Nazi Germany

It was nearly six weeks since the ‘Miracle of Dunkirk’ when 338,226 Allied troops were evacuated to Britain, some indeed in small boats and ships, but the majority in destroyers and transports, under continuous aerial attack in heavily mined waters.

The Germans were jubilant that summer. France and the Low Countries had fallen in one of the most brilliant campaigns of military history between protagonists of roughly equal strength. On June 22, the French had capitulated, signing the surrender in the Compiegne Forest using the same railway carriage where the Kaiser’s generals had surrendered to the Allies in 1918. Hitler went sightseeing the following day in Paris and visited Napoleon’s tomb.