Winterbotham, Frederick W. The Ultra Secret

Guarding the Secrets that won the Second World War

When British cryptographers at Bletchley Park decoded several messages from the German Air Force in April 1940, Group Captain Frederick Winterbotham recognised the potential of such information and set up a secure system for processing it. He created Special Liaison Units, small teams of RAF officers and enlisted personnel who received the decrypted Ultra messages and forwarded them securely to the appropriate commanders. These messages, transmitted via encrypted radio signals, were kept strictly secret, with the recipients unaware of their origin. Winterbotham's units played an important role at crucial moments during the war. His selected intercepted messages provided early insights into the collapse of France during the Battle of France and proved decisive in the Battle of Britain, North Africa, El Alamein and the D-Day invasion. The Ultra information was crucial to the Allies' military decisions, with Winston Churchill receiving urgent messages directly via a secure telephone line. By 1944, the system was highly efficient, providing time-critical information such as the rapid intelligence on the German evacuation of the Casino Line in Italy. Winterbotham also analysed the surprise of the Ardennes offensive of 1944-45 and concluded that the absence of German signals should have raised alarm bells. Winterbotham's first-hand account of the Enigma programme offers a unique perspective on its strategic importance.