The Broken Code: Churchill’s Dilemma At Coventry

At Bletchley, a tiny market town northwest of London, England, in November 1940, a terrible secret was learned. British code-breakers had managed to read German codes through an elaborate combination of stolen machines, Polish spies, interceptions, and brilliant and continuous decoding. The information gained in this way was called “Ultra”; it was gathered in the most careful and quiet way possible, and the British took great pains to keep the Germans from knowing that they had it. Obviously, if the Germans knew, they would simply adopt new codes, perhaps ones the British couldn’t break.

During the Battle of Britain, when Hitler was sending waves of planes, first to terrorize London, then to destroy England’s airfields, the code was somewhat helpful on early warning. Since the cities and airfields were obvious targets, the British could be expected to be ready with evacuation plans and fire engines. Other information, easily obtained by a modern nation, could be perceived in mid-flight; thus short-term, public adjustments could be made without creating suspicion.

But in November 1940 the cryptographers in Bletchley learned that Hitler was going to change his plans. Angrily responding to a bombing of Berlin which he had promised the German people could never occur, he decided suddenly to give up bombing strategic targets and instead bomb the nearby British provincial city of Coventry. The news was brought straight to Winston Churchill, the new prime minister, as one of the most terrible moral dilemmas of his career. If he acted on his knowledge, he would evacuate people and remove property, thus saving them; but he might also alert the Germans to the fact that he had “Ultra.”

It was a clear choice between the present and the future, and the future was unknown. How many secrets might be learned if the Germans failed to suspect the British? Even if the Germans suspected, would they give up their code? Might they give up their code anyway? What about the lives that would be lost needlessly? What about the property, which included the historic Coventry cathedral?

The Americans, not yet in the war, were not told of Churchill’s dilemma until the decision had been made. They might not have been much help. The U.S. Secretary of War, Henry L. Stimson, didn’t entirely believe in code-breaking; he believed that “gentlemen do not read each other’s mail.” And when Roosevelt learned of the situation, he said, “War is forcing us more and more to play God. I don’t know what I should have done.”

To Churchill, knowledge was desirable, even crucial, but it was also terrible. He dared not ignore it and he dared not act on it. What would you have done if you had been in his shoes?

Reprinted with the permission of Nancy Faust Sizer.