Beginning in early September 1943, invading German troops defeated both the Italian garrison in the Dodecanese and British forces sent to support them, aided by the fact that Allied units were operating without sufficient air cover.

The island of Leros, with its excellent deep-water port of Lakki (Portolago), was transformed into a heavily fortified aeronautical base, "the Corregidor of the Mediterranean", as Benito Mussolini, the Italian leader, boasted.

The main problem faced by the planners was the difficulty of countering Fliegerkorps X of the Luftwaffe because of a lack of air cover, as American and British aircraft were based in Cyprus and the Middle East.

A force based on the 8th Indian Infantry Division was assembled and American assistance in the form of P-38 Lightning long-range fighter squadrons was requested.

As a result of the Quebec Conference and the US refusal to assent to British plans, the forces and ships earmarked for Accolade were diverted barely a week before the surrender of Italy in the Armistice of Cassibile on 8 September.

Anticipating the Italian armistice, German forces, based largely in mainland Greece, had been rushed to many of the islands to maintain control.

The most important German force in the Dodecanese was the 7,500-strong Sturm-Division Rhodos (Assault Division Rhodes), commanded by Generalleutnant (Lieutenant-General) Ulrich Kleemann.

The next day, a British delegation, headed by George Jellicoe, was dropped by parachute on Rhodes, to persuade the Italian commander, Ammiraglio Inigo Campioni, to join the Allies.

[13] From 10 to 17 September, the 234th Infantry Brigade (Major-General Francis Brittorous) coming from Malta, together with 160 men from the Special Boat Service, 130 men from the Long Range Desert Group, a Company of the 11th Battalion, Parachute Regiment and Greek Sacred Band detachments had secured the islands of Kos, Kalymnos, Samos, Leros, Symi, Castellorizo and Astypalaia, supported by ships of the Royal Navy and Royal Hellenic Navy.

On 3 October, the Germans effected amphibious and airborne landings known as Unternehmen Eisbär (Operation Polar Bear) and reached the outskirts of Kos town later that day.

[18] On 4 October, German troops committed the Massacre of Kos, killing the captured Italian commander of the island, Colonnello Felice Leggio, and nearly 100 of his officers.

Leros had been subjected to air attack by the Luftwaffe beginning on 26 September which caused significant casualties and damage to the defenders of the island and supporting naval forces.

The Luftwaffe also intervened on 26 September, when 25 Junkers Ju 88s sank RHN Vasilissa Olga and HMS Intrepid at Lakki Bay, Leros.

From 22 to 24 October, HMS Hurworth and Eclipse sank in a German minefield east of Kalymnos, while RHN Adrias lost its prow.

The Germans bombed Samos with Ju 87 (Stukas) of I Gruppe, Stukageschwader 3 in Megara, prompting the 2,500-strong Italian garrison to surrender on 22 November.

Along with the occupation of the smaller islands of Patmos, Fournoi and Ikaria on 18 November, the Germans completed their conquest of the Dodecanese, which they held until the end of the war.

The Dodecanese campaign was one of the last British defeats in World War II and one of the last German victories, while others have labelled it a hapless fiasco which was badly conceived, planned and executed as a "shoestring strategy".

The operation was criticized by many at the time as another useless Gallipoli-like disaster and laid the blame at Churchill's door; perhaps unfairly so, since he had pushed for these efforts to be made far sooner, before the Germans were prepared.

Most of the Dodecanese Jews were murdered by the Germans; 1,700 members of the ancient Jewish community of Rhodes (of a population of about 2,000) were rounded up by the Gestapo in July 1944 and only some 160 of them survived the camps.

[citation needed] Italian prisoners of war were transferred to the mainland by the Germans in overcrowded, unseaworthy vessels, which led to several accidents, of which the sinking of the SS Oria on 12 February 1944 was the most deadly.