'Canter' (ii) was a British operation by elements of Major General J. S. Nichols’s 50^th Division and Major General D. N. Wimberley’s 51^st Division of Lieutenant General Sir Oliver Leese’s XXX Corps in General Sir Bernard Montgomery’s 8^th Army to secure an initial breakthrough of the Axis positions in the Mareth Line at the south-eastern corner of Tunisia (16/22 March 1943).

The Mareth Line was a system of fortifications built by the French between the towns of Medenine and Gabès in the south-eastern Tunisia before World War II. It was designed to defend against any attacks Italian incursion to the west from Libya, but after the fall of France in June 1940 and the Allied 'Torch' landings of November 1942, it fell into Axis hands and was used by the Italians and Germans to defend against the advance of the 8^th Army from the east.

Central Tunisia is dominated geographically by the eastern end of the Atlas mountains, while the northern and southern portions are largely flat. The primary feature in the south is the Matmâta hills, a range running north/south essentially parallel to the eastern coast on the Mediterranean Sea. to the west of the hills, the land is inhospitable desert, making the region between the hills and the coast the only easily navigable approach to the settled areas of the north. A smaller line of hills runs east/west along the northern edge of the Matmâta range, complicating this approach still further. There is a small gap between the two ranges, the Tebaga Gap, at the extreme northern exit of the Matmâta hills.

The Mareth Line is general followed the Wadi Zigzaou for 22 miles (35 km) inland from the sea to the Matmâta hills, crossing the coastal road. The wadi provided a natural defence line, with steep banks some 70 ft (21 m) high in places, and the Mareth Line was often conceded to be the most difficult military defence line in North Africa. The French view was that the hills were sufficiently impassable to discount any attempt to outflank on the landward side, a fact which was later disproved in 'Supercharge II'.

The Mareth Line was modelled conceptually on the Maginot Line, and was often dubbed the Ligne Maginot du Désert (Maginot Line of the desert). Built between 1936 and 1940, the Mareth Line included 28 miles (45 km) of fixed defences, and its core was a network of 40 infantry bunkers, eight large artillery bunkers, 15 command posts and 28 support posts.

Although constructed to counter a possible Italian incursion into Tunisia, the Mareth Line played no part in the Franco-Italian war of June 1940 as the North African theatre remained relatively peaceful. After the fall of France, the Mareth Line was formally demilitarised by a joint Italo-German commission. Then, after the Axis defeat in the 2^nd Battle of El Alamein during November of 1942, the Germans began to remilitarise and refurbish the Mareth Line for use as the British 8^th Army moved to the west in pursuit of the Deutsch-Italienische Panzerarmee at it retired toward and then into Tunisia. By March 1943 more than 62 miles (100 km) of barbed wire entanglements had been laid, as well as 100,000 anti-tank mines and 70,000 anti-personnel mines. In addition, the bunkers had been reinforced with additional concrete and rearmed with anti-tank and anti-aircraft guns.

After the British success at El Alamein, the German and Italian forces had conducted a fighting retreat across northern Libya and into Tunisia. Montgomery’s 8^th Army paused at Medenine to prepare for the difficult assault on the Mareth Line and the Italian 1^st Army attempted a pre-emptive attack in 'Capri'. When this failed, the Axis troops withdrew to the Mareth Line and awaited the British attack.

The Axis defence of the Mareth Line was centred on Generale di Divisione Nino Sozzani’s 136a Divisione motorizzata 'Giovani Fascisti', Generale di Divisione Francesco La Ferla’s 101a Divisione motorizzata 'Trieste' and Generalleutnant Theodor Graf von Sponeck’s 90^th leichte Afrikadivision of Generale di Corpo d’Armata Taddeo Orlando’s XX Corps and, to its south, Generale di Brigata Gavino Pizzolato’s 80^th Divisione aviotrasportabili 'La Spezia', Generale di Divisione Giuseppe Falugi’s 16^th Divisione motorizzata 'Pistoia' and General Kurt Freiherr von Liebenstein’s 164^th leichte Afrikadivision of Generale di Corpo d’Armata Paulo Berardi’s XXI Corps. In reserve was Generalleutnant Willibald Borowitz’s 15^th Panzerdivision.

Both of these corps were part of Generale d’Armata Giovanni Messe’s Italian 1a Armata (latterly the Deutsch-Italienische Panzerarmee commanded by Generalmajor Karl Bülowius, who had followed Generalfeldmarschall Erwin Rommel in command on 17 February). The Italian 1a Armata was a formation of Heeresgruppe 'Afrika', which had been created on 22 February under the command of Rommel to control the Tunisian operations of the Italian 1a Armata and General Gustav von Vaerst’s 5^th Panzerarmee.

With the semi-favourable conclusion of his operations in central Tunisia against the forces of Lieutenant General K. A. N. Anderson’s Allied 1^st Army in and around the Kasserine Pass, Rommel was able to turn the 1^st Army back toward the east, where the 8^th Army was approaching the Mareth Line defences and would inevitably attempt to break through these to link with the Allied 1^st Army.

As soon as reconnaissance and intelligence warned him that Borowitz’s 15^th Panzerdivision and Generalleutnant Hans-Georg Hildebrandt’s (from 15 March Generalmajor Heinrich-Hermann von Hülsen’s) 21^st Panzerdivision of von Vaerst’s 5^th Panzerarmee were moving to the south in the direction of the Mareth Line, Montgomery reinforced the elements of his 8^th Army around Medenine, just to the south-east of Mareth, and instructed his forward formations to dig in behind barbed wire entanglements and minefields.

In overall terms Montgomery’s scheme was to destroy any German concentrations with his superior artillery, and to reserve his own armour for deployment only in the event that a German tank breakthrough threatened.

On 6 March Rommel committed his forces in the 'Capri' wide-front offensive to the west and north-west of Medenine, the main pressure being exerted by the 15^th Panzerdivision and 21^st Panzerdivision in the centre, to the south-west of Hir Ksar Koutine in the area held by Brigadier L. G. Whistler’s 131^st Lorried Brigade and Brigadier J. A. Gascoigne’s 201^st Guards Lorried Brigade of Major General G. W. E. J. Erskine’s 7^th Armoured Division. Further weight was added to the German attack by Generalleutnant Friedrich Freiherr von Broich’s 10^th Panzerdivision against the area held by Brigadier H. Kippenberger’s New Zealand 5^th Brigade of Lieutenant General Sir Bernard Freyberg’s New Zealand 2^nd Division.

All of the German attacks, complemented in the north by the efforts of Pizzolato’s 80a Division aviotrasportabile 'La Spezia' and von Sponeck’s 90^th leichte Afrikadivision against the area held by Brigadier J. E. Stirling’s 154^th Brigade of the 51^st Division, were checked and thrown back by artillery and anti-tank fire. The Axis forces made another attack in the afternoon of the same day, and were again repulsed, the German divisions having lost 50 of their 150 tanks. There the situation rested for the next fortnight as Montgomery finalised his plan to break through the Mareth Line defences to which the Axis forces had fallen back after 6 March.

At 22.30 on 20 March the 8^th Army’s artillery opened fire on the 1a Armata's formations. Extending from the Matmata hills north to the Gulf of Gabès, these comprised Berardi’s XXI Corps and Orlando’s XX Corps. Half an hour later, the 'Canter' (ii) attack of the XXX Corps moved forward in the coastal sector. This frontal offensive was accompanied by the 'Pugilist-Gallop' flanking attack carried out by Freyberg’s New Zealand Corps (New Zealand 2^nd Division and Brigadier C. B. C. Harvey’s British 8^th Armoured Brigade) which, advancing along the corridor bounded on the left by the Grand Erg and on the right by the Matmâta hills, would take the El Hamma pass, held by Generale di Corpo d’Armata Alberto Mannerini’s Raggruppamento Sahariano, and dash for Gabès, where he could cut the Italian 1a Armata's lines of communication and retreat.

As El Hamma is 120 miles (195 km) distant from Foum-Tatahouine, Freyberg had begun the advance of his formation, reinforced by Général de Division Philippe François Marie Jacques Leclerc de Hauteclocque’s Free French column, on 18 March.

On the afternoon of the first day, heavy rain had turned the Wadi Zigzaou into a saturated wallow across the front of the Mareth positions and formed an anti-tank ditch 40 yards (37 m) wide and 12 ft (3.5 m) deep, so that by dawn on 21 March only six of the 50^th Royal Tank Regiment’s tanks had managed to get through to the opposite side and support the 50^th Division, which had managed to penetrate the Mareth Line at Zarat but was now having a very hard time of it under the concentrated fire of the 136^th Divisione motorizzata. An attempt by the Royal Engineers' bulldozers to breach the bank of the Wadi Zigzaou fared no better. Then the 15^th Panzerdivision, which was being held in reserve, counterattacked with great vigour: by 23 March the attackers had managed to gain and hold only one foothold on the left bank to the west of Zarat.

Faced with this heavy setback, Montgomery already decided on an alternative plan. While Major General F. I. S. Tuker’s Indian 4^th Division attacked the Matmâta hills on Messe’s right flank, the X Corps and Major General R. Briggs’s 1^st Armoured Division had been released in the wake of the New Zealand 2^nd Division, and in order to deceive the Axis forces still further, the 7^th Armoured Division had been brought into the line. The ruse did not have as much success as had been hoped for it, for by 21 March Messe had already got wind of Freyberg’s 'Pugilist-Gallop' move and sent both von Liebenstein’s 164^th leichte Afrikadivision and von Hülsen’s 21^st Panzerdivision toward El Hamma to prevent the arrival on the Axis forces' right flank of any British and commonwealth force which had managed to cross the Matmâta hills from east to west via Wilder’s Gap and then moved north to pass through the Tebaga Gap between the Matmâta hills and Djebel Tebaga in the Axis forces' rear. Thus was set the scene for 'Supercharge II'.