commands agreed to fight a delaying action in the north-east. The British did not move their troops, because General Wilson regarded them as too weak to protect such a broad front. Instead, he took a position some west of the Axios, across the Haliacmon Line. The two main objectives in establishing this position were to maintain contact with the Hellenic army in Albania and to deny German access to Central Greece. This had the advantage of requiring a smaller force than other options, while allowing more preparation time, but it meant abandoning nearly the whole of Northern Greece, which was unacceptable to the Greeks for political and psychological reasons. The line's left flank was susceptible to flanking from Germans operating through the Monastir Gap in Yugoslavia. The rapid disintegration of the Yugoslav Army and a German thrust into the rear of the Vermion position was not expected. The German strategy was based on using so-called "blitzkrieg" methods that had proved successful during the invasions of Western Europe. Their effectiveness was confirmed during the invasion of Yugoslavia. The German command again coupled ground troops and armour with air support and rapidly drove into the territory. Once Thessaloniki was captured, Athens and the port of Piraeus became principal targets. Piraeus, was virtually destroyed by bombing on the night of the 6/7 April. The loss of Piraeus and the Isthmus of Corinth would fatally compromise withdrawal and evacuation of British and Greek forces. Defence and attack forces The Fifth Yugoslav Army took responsibility for the south-eastern border between Kriva Palanka and the Greek border. The Yugoslav troops were not fully mobilised and lacked adequate equipment and weapons. Following the entry of German forces into Bulgaria, the majority of Greek troops were evacuated from Western Thrace. By this time, Greek forces defending the Bulgarian border totalled roughly 70,000 men (sometimes labelled the "Greek Second Army" in English and German sources, although no such formation existed). The remainder of the Greek forces—14 divisions (often erroneously referred to as the "Greek First Army" by foreign sources)—was committed in Albania. On 28 March, the Greek Central Macedonia Army Section—comprising the 12th and 20th Infantry Divisions—were put under the command of General Wilson, who established his headquarters to the north-west of Larissa. The New Zealand division took position north of Mount Olympus, while the Australian division blocked the Haliacmon valley up to the Vermion range. The RAF continued