On the 20th May 1941 the invasion of Crete by German forces began

The Battle of Crete was the first airborne invasion in military history and due to heavy losses of aircraft and troops it was the only occasion airborne forces were used operationally by the German Army. It was also the first time the Allies made significant use of intelligence from decrypted German messages from the Enigma machine.

British forces had initially been garrisoned on Crete when the Italians attacked Greece in October 1940. By April 1941 The British Commonwealth contingent consisted of the original 14,000 strong British garrison and another 25,000 British and Commonwealth troops evacuated from the Greek mainland including the British 14th Infantry Brigade.

Royal Signals & Middlesex Yeomanry Special Wireless Section

A Royal Corps of Signals Section supported 14th Infantry Brigade and a Special Wireless Section from 1st Middlesex Yeomanry had deployed to Crete in April 1941 to monitor German signal activity. Wireless intercepts successfully identified a German invasion convoy heading for Crete on 21 May and aircraft reconnaissance was able to locate the convoy resulting in the Royal Navy sinking 12 ships and the convoy being recalled.

Communication delays lead to loss of Crete

As a result of wireless intercepts the Allies were aware of the impending German invasion but delays in relaying this information to commanders on the ground and then intelligence being misinterpreted and taken out of context, the German forces ultimately gained the upper hand resulting in the loss of Crete and the evacuation of Allied forces to North Africa at the end of May.