 Following the fall of Tripoli in January 1943 , the remaining Axis forces retreated to prepared defences in Southern Tunisia , in front of the Mareth Line built by France before the war . Here in March , Horrocks carried out one of his most successful actions . His corps , composed of the 1st Armoured Division , a Free French brigade and the attached New Zealand Corps ( which included the 2nd New Zealand Division and the British 8th Armoured Brigade ) , was ordered to attack as part of Operation Supercharge after XXX Corps failed to breach the line . He carried out a flanking manoeuvre through a pass judged by the Germans to be impenetrable , rendering the Mareth position untenable and forcing the Axis into another retreat . Three Italian divisions were destroyed , and the German 15th Panzer Division , 21st Panzer Division and 164th Division were heavily depleted . Horrocks was then transferred to the First Army to take over IX Corps after its previous commander , Lieutenant @-@ General John T. Crocker , was wounded in a training accident . He led this corps in the final Allied offensive in Tunisia during April and May 1943 , capturing Tunis and accepting the surrender of the remnants of Rommel 's Army Group Africa . He was mentioned in despatches on 24 June , and for his service in Tunisia , was appointed a Companion of the Order of the Bath on 5 August . He was also given the rank of temporary lieutenant @-@ general and war substantive major @-@ general . 
