This was an Allied unrealised plan by Field Marshal the Hon. Sir Harold Alexander’s (later General Mark W. Clark’s) Allied 15th Army Group to take the ports of Split, Sibenik and Zara on the coast of German-occupied Yugoslavia as a means of facilitating the movement of Lieutenant General Sir Richard McCreery’s British 8th Army across the Adriatic Sea to capitalise on the success of Marshal Josef Broz Tito’s Yugoslav forces by driving to the north into Austria (autumn 1944/spring 1945).
Alexander had long desired to outflank the German defences in northern Italy, where the Allies and the Germans were nicely balanced, and at the time when it was assumed that the Allied Armies in Italy (from 11 December 1944 the 15th Army Group) would reach the Adige river by the winter of 1944 he had ordered that three British divisions be prepared for withdrawal from the line for training in amphibious operations.
This initial plan supposed a major amphibious operation across the Adriatic Sea, but Tito’s successes along the coast led Alexander to revise his scheme, which was now that light forces and commandos should be landed at the three ports in question to aid Tito and to develop the ports and their inland communications so that the 8th Army could be moved across the Adriatic for a rapid development into southern Austria. It was too late by the time Alexander had formulated his scheme, however, for the Allied armies had not pushed far enough to the north by the advent of winter, the US Joint Chiefs-of-Staff were opposed to the development of another operational front in the Mediterranean theatre, the growing civil war in Greece was absorbing three divisions (Major General F. I. S. Tuker’s Indian 4th Division, Major General A. D. Ward’s British 4th Division and Major General C. E. Weir’s British 46th Division of Lieutenant General J. L. I. Hawkesworth’s British X Corps), and Tito was becoming totally disillusioned with the half-hearted support he was receiving from the Western Allies, especially as politically sympathetic Soviet forces were already operating in northern and eastern Yugoslavia. Prime Minister Winston Churchill also pointed out that Yugoslav operations by the British in February 1945 were far too late to have any material effect on the outcome of the war.