 On 2 March , Operation Lustre — the transportation of troops and equipment to Greece — began and 26 troopships arrived at the port of Piraeus . On 3 April , during a meeting of British , Yugoslav and Greek military representatives , the Yugoslavs promised to block the Struma valley in case of a German attack across their territory . During this meeting , Papagos stressed the importance of a joint Greco @-@ Yugoslavian offensive against the Italians , as soon as the Germans launched their offensive . By 24 April more than 62 @,@ 000 Empire troops ( British , Australians , New Zealanders , Palestine Pioneer Corps and Cypriots ) , had arrived in Greece , comprising the 6th Australian Division , the New Zealand 2nd Division and the British 1st Armoured Brigade . The three formations later became known as ' W ' Force , after their commander , Lieutenant @-@ General Sir Henry Maitland Wilson . Air Commodore Sir John D 'Albiac commanded British air forces in Greece . 
