Mareth Line

In the 1930s the defence of the French colonial empire (French Indochina, Pacific Islands, West Indies, African colonies and Syria–Lebanon) was left to the French Foreign Legion, colonial and "native" units, the Marine nationale (Navy) and the Armée de l'Air (Air Force). By the late 1930s, the Navy had only one aircraft carrier and the Armée de l'Air could spare only second-rate aircraft. Algeria, Morocco and Tunisia provided much of the manpower of the Armée coloniale and Tunisia, with the Italian colony of Libya to the east, was excepted from the priority given to the defence of metropolitan France.[1] French plans for defence of Tunisia assumed that Italy would launch an overwhelming assault that France could not easily oppose. Italy was expected to launch attacks on Egypt and Tunisia as soon as war was declared, with the Italian Navy securing supply and blocking any substantial Anglo-French relief. With a force of six divisions, a fortress division and a cavalry division to defend Tunisia, capable of only local operations with limited objectives. The French army considered the construction of a "Maginot Line in the desert" (ligne Maginot du désert).[2][lower-alpha 1]

Central Tunisia is dominated by the Atlas Mountains, while the northern and southern portions are largely flat. The primary feature in the south is the Matmata Hills, a range running north-south roughly parallel to the Mediterranean coast. West of the hills, the land is the inhospitable Jebel Dahar and the Dehar region of desert beyond to the west, making the region between the hills and the coast the only easily traversed approach to northern Tunisia.[4] A smaller line of hills runs east–west along the northern edge of the Matmata range, further complicating this approach. At the far northern end of the Matmata Hills is the Tebaga Gap. From the Mediterranean the coastal plain rises gently to the Matmata Hills. The plain consists of gravels and sands, with salt flats between the sandy areas, which turn into bogs after light rain becoming impassable to wheeled vehicles. There are numerous wadis from the hills to the sea, including the bigger Wadi Zeuss and Wadi Zigzaou. Inland, the sources of the wadis are steep and rocky, widening near the coast, the beds having streams or muddy bottoms, with firmer areas traversable by vehicles.[5]

Topographic map of Tunisia

In January 1934 planning began on the new fortifications; Infantry officers selected the sites for strongpoints to dominate the ground in front with overlapping fields of fire. In 1936, the French government provided funds for construction after Italy formed the Rome–Berlin Axis with Germany, creating a greater threat to French security in North Africa.[6][lower-alpha 2] The casemates designed for the line had much less concrete than comparable examples in France and had no fossé (gap) rather a stable door, in case the lower part was blocked by débris. In September 1936, during a meeting with General Joseph Georges, it was agreed that the fortification of the Mareth Line, Bizerte, Medenine, Ben Gardane and Foum Tataouine (Tataouine) must be completed. Medenine, Ben Gardane to the west and Tataouine to the east, were south of the proposed line, Tataouine being the place where the routes to Mareth passed through the bottleneck between the Matmata Mountains and the sea.[6]

The line was divided into eastern and western sectors with a main line of resistance and a reserve line about 0.93 mi (1.5 km) back. A secteur défensif (SD) was to be built on the rocky Dahar Plateau, which later became part of an SD across the Matmata Hills to Kebili on the edge of the Chott el Djerid. The chott and Chott El Fedjaj drained across Tunisia into Wadi Akarit, across Tunisia but Wadi Akarit was only sketchily fortified, the French concentrating on the Mareth Line 31 mi (50 km) south, to cover Gabes.[6] The gap between the Mareth Line and the Great Eastern Sand Sea, a potential route by which an invader could outflank the Mareth line, was not given consideration until 1938. General Georges Catroux and Colonel Gautsch surveyed the area and in their assessment predicted that three divisions could advance from the Libyan border to Ksar (fortified village) el Hallouf and Bir (well) Soltane in six days and then advance into the gaps either side of Djebel Melab and those between Djebel Tebaga and the Matmata Hills. [7]

The Second World War began in 1939 but the Mareth Line was inactive from 1939 to 1940, as Italy remained neutral until a few days before the Armistice of 22 June 1940, after which, the line was demilitarised by an Italo-German commission. In November 1942, the British Eighth Army (General Bernard Montgomery) defeated Panzerarmee Afrika at the Second Battle of El Alamein and the British First Army landed in French North Africa in Operation Torch. Axis forces occupied Tunisia in the Tunisia Campaign and from November 1942 to March 1943, the Panzerarmee conducted a fighting retreat through Egypt and Libya, pursued by the Eighth Army. In March the Eighth Army reached the Libya–Tunisia border and paused at Medenine to prepare to attack the Mareth Line. Axis engineers built an outpost zone from Wadi Zeuss 3.5 mi (5.6 km) back to the Mareth Line. Field fortifications were constructed at Sidi el Guelaa, south of Aram on the main road from Medinine to Mareth, around Aram and at Bahira. The Mareth Line was refurbished for occupation by the Panzerarmee and by March 1943, more than 62 miles (100 km) of barbed wire, 100,000 anti-tank mines and 70,000 anti-personnel mines had been laid, bunkers had been reinforced with concrete and armed with anti-tank and anti-aircraft guns.[8]

The Axis forces opposing the Eighth Army were renamed the Italian 1st Army (General Giovanni Messe) on 23 February 1943 and attempted a spoiling attack, the Battle of Medenine (Unternehmen Capri, Operation Capri). The attack was a costly failure and the Axis troops withdrew to the Mareth Line to await the British attack.[9] Rommel called the Mareth Line "a line of antiquated French blockhouses, which in no way measured up to the standards required by modern warfare...".[10] The Mareth Line was garrisoned by the 136th Infantry Division "Giovani Fascisti" from the coast to Zarat, the 101st Motorised Division "Trieste" covering the Gabès–Mareth road around Mareth and Aram, the 90th Light Division to the south of the "Trieste" Division at Aram and Sidi el Guelaa cutting the road and covering Wadi Zeuss, 80th Infantry Division "La Spezia" south of the 90th Light Division, the 16th Motorised Division "Pistoia". South of "La Spezia", near Beni Kreddache covering the Hallouf Pass the line was held by the 164th Light Afrika Division. The 15th Panzer Division with 32 operational tanks was based at Zerkine 5 mi (8.0 km) north-west of Mareth. In reserve were the 21st Panzer Division south-west of Gabès and the 10th Panzer Division south-west of Sousse with 110 operational tanks. The line from Djebel Tebaga to Djebel Melab was held by the Raggruppamento Sahariano.[11][lower-alpha 3] The British survey of the Mareth Line, the positions of Zarat sudest (Zaret South-West), Ouerzi, Ouerzi Ouest (Ouerzi West), Ouerzi Est (Ouerzi East), Ksiba Ouest and Ksiba Est being of particular interest, was assisted by General Marcel Rime-Bruneau, a former Chief of Staff of the Tunisian garrison and Captain Paul Mezan, the former Garrison Engineer of the Mareth Line.[5]

Infantry bunker of the Mareth Line

On 19 March 1943, the Eighth Army made a frontal assault against the Mareth Line in Operation Pugilist. The 50th Northumbrian Infantry Division penetrated the Line near Zarat but was driven back by the 15th Panzer Division and the "Giovani Fascisti" on 22 March.[12] Reconnaissance by the Long Range Desert Group had shown that the line could be outflanked. A force could pass through the southern Matmata Hills, reach the Tebaga Gap from the west and reach the coastal plain behind the Mareth Line. During Pugilist, Montgomery had sent the 2nd New Zealand Division around the Matmata Hills but its attack was contained at the Tebaga Gap from 21 to 24 March. Montgomery sent the 1st Armoured Division (X Corps) to reinforce the attack at the Tebaga Gap. The British attacked again in Operation Supercharge II on 26 March and broke through the gap the next day. This success, combined with another frontal assault on the Mareth Line, made the position untenable; the Italian 1st Army escaped encirclement when the 1st Armoured Division was held up at El Hamma and the Axis forces retreated to Wadi Akarit, 37 mi (60 km) to the north.[13]