Allied radio intercepts and ultra intelligence revealed the broad outlines of the German plan, which consisted of airborne assaults and a sea invasion. They did not reveal the relative strength of these attacks, however. Particularly serious for the British forces was the lack of air assets. By 18 May, German air attacks on Crete had left the defenders with only a dozen aircraft, and Britain's one aircraft carrier, the Formidable, began the battle with only four serviceable planes. While patrolling the island to prevent a German seaborne landing, Royal Navy sailors, exhausted from their role in the evacuation from Greece, were exposed to the full weight of the Luftwaffe's 700 combat aircraft operating from bases in Greece, as well as occasional Italian air strikes.
The German assault on Crete, Operation merkur ( mercury) began on 20 May. German air superiority forced the Royal Navy's warships to retire south of Crete during the day, and the defenders rarely managed to put more than a dozen planes in the air at any one time. Long-range bombing of the Luftwaffe's bases in Greece by British aircraft based in Malta and Egypt failed to affect German air operations in any material way.
On the night of 21–22 May, British warships intercepted two lightly escorted troop convoys, each composed of 20 small, overloaded coastal vessels packed with troops and escorted by a single Italian torpedo boat. In one-sided engagements, British cruisers and destroyers sank 10 ships in one convoy and 2 in the other. Only the British squadron's need to retire south before daybreak to protect it from Axis air attack saved the second convoy from total destruction. The surviving ships of both convoys returned to Greece. Some 400 German soldiers were lost in this effort, and Germany thereafter relied entirely on air supply and reinforcement in its invasion.
Despite the best efforts of the Royal Navy and the defenders on the ground, it became impossible to defend the island once German troops had captured Máleme Airfield. On 26 May, with the situation hopeless, island commander Major General Bernard Freyberg ordered an evacuation. Once again, the Royal Navy rushed to rescue Commonwealth and Allied soldiers (wags said that BEF stood for "Back Every Fortnight").
The long distances involved and the Luftwaffe's complete control of the air made the evacuation particularly difficult, but the British commander in the Mediterranean, Admiral Andrew B. Cunningham, ordered his ships to continue the evacuation regardless of cost. Despite constant German air attack, they managed to evacuate almost 18,000 of Crete's 32,000 defenders, but the Royal Navy suffered very high losses itself in the process. In the weeklong operation, German air attacks sank three cruisers, six destroyers, and several smaller vessels and inflicted serious damage on the Formidable, the battleships Barham and Warspite, three cruisers, and numerous other warships. Few British warships escaped without damage, and some 2,000 British sailors died, along with a similar number of evacuated soldiers. In the course of the fight, many ships completely exhausted their antiaircraft ammunition. The Luftwaffe lost only a few dozen aircraft.
Stephen K. Stein
MacDonald, Callum. The Lost Battle: Crete 1941. New York: Free Press, 1993.; Pack, S. W. C. The Battle for Crete. Annapolis, MD: Naval Institute Press, 1973.; Roskill, Stephen W. The War at Sea, 1939–1945. Vol. 1. London: Her Majesty's Stationery Office, 1954.; Spector, Ronald. At War at Sea. New York: Viking, 2001.; Thomas, David. Crete 1941: The Battle at Sea. London: New English Library, 1975.