Endgame
The salient at Medjez had been relieved and lateral roads in the V Corps area cleared so that Anderson was able to turn his full attention to the orders he had received on 12 April from Alexander to prepare the large-scale attack, scheduled for 22 April, to gain Tunis.
By this stage, Allied aircraft had been moved forward to airfields in Tunisia to prevent the aerial supply of Axis troops in North Africa (Operation Flax) and large numbers of German transport aircraft were shot down between Sicily and Tunis. British destroyers operating from Malta prevented marine supply, reinforcement or evacuation of Tunisia by sea (Operation Retribution). Admiral Cunningham, Eisenhower's Naval Task Force commander, issued Nelsonian orders to his ships: "Sink, burn, capture, destroy. Let nothing pass".
By 18 April, after attacks by Eighth Army from the south and flanking attacks by IX Corps and French XIX Corps the German-Italian forces had been pushed into a defensive line on the north-east coast of Tunis, attempting to protect their supply lines, but with little hope of continuing the battle for long.
Read more about this topic: Tunisia Campaign