'Vulcan' was the Allied final offensive by General the Hon. Sir Harold Alexanderï' Allied 18^th Army Group to destroy the Axis forces of Generaloberst Hans-Jürgen von Arnimï's Heeresgruppe 'Afrika' in its Tunisian lodgement (22 April/6 May 1943).

On 26 February von Arnim, currently commanding the 5^th Panzerarmee and wrongly believing that the Kasserine battles had forced the Allies to weaken their forces in northern Tunisia in order to reinforce those in the south, launched 'Ochsenkopf' (i) with the approval of Generalfeldmarschall Albert Kesselring, the Oberbefelhshaber 'Süd', but without even consulting Generalfeldmarschall Erwin Rommel, then commander of Heeresgruppe 'Afrika'. This was a wide-front offensive against Lieutenant General C. W. Allfrey’s British V Corps by Generalleutnant Friedrich Weber’s Gruppe 'Weber', which included Weber’s own 334^th Division, newly arrived elements of Generalmajor Paul Conrath’s Division 'Hermann Göring', and those elements of Generalleutnant Friedrich Freiherr von Broich’s 10^th Panzerdivision which had not been involved in 'Frühlingswind'. Weber’s force was to advance in three groups: one to the west in the direction of Medjez el Bab; another, in the area to the north of the first group, to the south-west on the route from Mateur to Béja, some 25 miles (40 km) to the west of Medjez el Bab; and the last to the west in the area some 25 miles (40 km) to the south of Medjez el Bab. The northern flank of Weber’s force was to be protected by Generalleutnant Hasso-Eccard Freiherr von Manteuffel’s Division 'von Manteuffel' advancing to the west and forcing the Allies out of their advanced positions opposite the so-called Green Hill and the Axis-held Jefna station.

In fierce fighting, the German attack on Medjez el Bab was defeated by Major General V. Evelegh’s British 78^th Division, but farther to the south the Germans achieved some tactical gains before being checked. In the north progress was made towards Béja in fighting which lasted to 5 March and in very bad weather, but the attack was blunted at Hunt’s Gap, some 15 miles (24 km) to the north-east of Béja, by Brigadier H. A. James’s 128^th Brigade of Major General H. A. Freeman-Attwood’s 46^th Division with the aid of substantial artillery and two tank squadrons of the North Irish Horse. von Arnim’s attack in the north by the Division 'von Manteuffel' made good progress across the hills, only lightly held by the French, between Cap Serrat and the railway town of Sedjenane. Costly counterattacks on 27 February and 2 March by elements of Brigadier R. C. Chichester-Constable’s (on a temporary basis from 3 March Brigadier B. Howlett’s) 139^th Brigade of the 46^th Division, together with attached units (No. 1 Commando and supporting artillery) delayed the Axis advance. However, the German took Sedjenane on 4 March and the 139^th Brigade was pushed slowly back over the next three weeks some 15 miles (24 km) in the direction of Djebel Abiod.

von Arnim abandoned his attacks in the centre and south, but the withdrawal of French battalions in the Medjez el Bab area to join Général de Corps d’Armée Marie Louise Koétz’s XIX Corps d’Armée allowed the German commander to occupy the high ground dominating the town, which was thus left in a dangerous salient.

On 25 March Alexander ordered his forces to regain the initiative on the V Corp' front. On 28 March Lieutenant General K. A. N. Anderson’s Allied 1^st Army launched the 46^th Division (one brigade up and one brigade down, reinforced by the attachment of Howlett’s 36^th Brigade, Brigadier E. W. C. Flavell’s 1^st Parachute Brigade and French units including a tabor (battalion) of specialist mountain warfare goumiers, supported by the artillery of two divisions plus more from army resources. In four days it succeeded in recapturing all ground taken by the Division 'von Manteuffel' and also took 850 German and Italian prisoners.'

On 7 April Anderson ordered the 78^th Division to clear the road linking Béja and Medjez el Bab. Supported by artillery and close support aircraft, the formation advanced methodically for 10 miles (16 km) through difficult mountain terrain in a 10-day period, clearing a front some 10 miles (16 km) wide. Major General J. L. I. Hawkesworth’s British 4^th Division then made its combat debut as it took position on 78^th Division’s left and advanced toward Sidi Nisr. Thus the salient at Medjez el Bab had been relieved and the lateral roads in the V Corps' area cleared so that Anderson could concentrate on the orders he had received on 12 April from Alexander to prepare the definitive 'Vulcan' offensive, scheduled for 22 April, to take Tunis.

By this stage of the campaign, Allied aircraft had been moved forward to airfields in Tunisia to prevent the aerial supply of Axis troops in North Africa in 'Flax', and large numbers of German and Italian transport aircraft were shot down between Sicily and Tunis. British destroyers operating from Malta in the 'Retribution' naval counterpart of 'Flax' similarly prevented Axis maritime supply, reinforcement or evacuation of Tunisia.

By 18 April, after attacks by General Sir Bernard Montgomery’s British 8^th Army from the south and flanking attacks by Lieutenant General J. T. Crocker’s British IX Corps and the French XIX Corps d’Armée, the Axis forces had been pushed back into a defensive lodgement on the north-east coast of Tunis, attempting to protect their supply lines, but having little hope of fighting a further-prolonged campaign. The Allied 18^th Army Group (1^st Army, 8^th Army, Lieutenant General Omar N. Bradley’s US II Corps and Koéltz’s French XIX Corps d’Armée) was now ordered by General Dwight D. Eisenhower, the Allied commander-in-chief in the North African theatre, to complete the destruction of Heeresgruppe 'Afrika' (Generale d’Armata Giovanni Messe’s Axis 1^st Army and General Gustav von Vaerst’s 5^th Panzerarmee) and so terminate the North African campaign.

The US II Corps was to advance on Bizerte. In the event, the US 9^th Division pressed toward Djebel Cheniti, the US 1^st Armored Division encountered heavy resistance at Djebel el Messeftine, and the US 34^th Division advanced beyond Eddekhila. The French XIX Corps advanced toward Pont du Fahs against scattered German and Italian resistance. As it moved toward Tunis, the British V Corps destroyed the 15^th Panzerdivision with heavy ar tillery and air bombardment. The British IX Corps attacked toward Tunis with the British 4^th Division and Indian 4^th Division abreast. The British 6^th and 7^th Armoured Divisions were tasked to exploit any breaks in the Axis forces' defensive line.

Alexander issued his orders for 'Vulcan' on 16 April, in them fixing the 1^st Army’s tasks as the capture of Tunis, co-operation with the US II Corps in the capture of Bizerte and, if necessary, co-operation with the 8^th Army for the capture of the Cap Bon peninsula, fixing the II Corps' task as the capture of Bizerte, and fixing the 8^th Army’s tasks as exerting pressure in the south to draw off the 1^st Army and an offensive to Hammamet and Tunis to prevent the Axis forces falling back into the Cap Bon peninsula. The operation was to be supported throughout by Air Marshal Sir Arthur Coningham’s North-West African Tactical Air Force, with Air Commodore K. B. B. Cross’s No. 242 Group of the RAF, Brigadier General Paul L. Williams’s US XII Air Support Command and Air Commodore L. F. Sinclair’s North-West African Tactical Bomber Force allocated to the Allied 1^st Army, and Air Vice Marshal H. Broadhurst’s Western Desert Air Force to the 8^th Army.

Within this overall scheme, Alexander planned that in the north the US II Corps would attack to the east in the direction of Mateur and Bizerte, in the left centre the 1^st Army would attack to the north-east in the direction of Massicault and Tunis, in the right centre the XIX Corps d’Armée would attack to the north-east in the direction of Pont du Fahs and Ste Marie du Zit, and in the south the 8^th Army would attack to the north from Enfidaville in the direction of Hammamet and the Cap Bon peninsula.

Anderson was to co-ordinate the actions of 1^st Army and US II Corps, and his plan fixed the primary attack as that in the centre of the V Corps' front at Medjez el Bab, on the left of the 1^st Army and confronting main Axis defences. However, the IX Corps on the 1^st Army’s right would first attack to the north-east and advance as rapidly as possible to get in behind the defences of Medjez el Bab and disrupt the Axis armoured reserves. The US II Corps would make a double thrust: one to capture the high ground around Sidi Nsir on the V Corps' left flank and the other toward Bizerte. The French XIX Corps d’Armée would be held back until the IX Corps and 8^th Army had drawn in the opposition, and then advance towards Pont du Fahs.

By this time the Allied forces had been reorganised. The advance to the north by the 8^th Army had pinched out the US II Corps' east-facing front in the area of Gafsa, allowing the whole corps to be withdrawn and switched to the northern end of the Allied front.

von Arnim knew that an Allied offensive was imminent and launched a spoiling attack on the night of 20/21 April between Medjez el Bab and Goubellat, and also on the IX Corps' front. The Division 'Hermann Göring', supported by tanks of the 10^th Panzerdivision, punched through to a depth of as much as 5 miles (8 km) at some points, but could not force a general withdrawal, and eventually returned to their lines. No serious disruption was caused to Allied plans, although the first attack of the offensive, by IX Corps, had to be delayed by four hours from 04.00 to 08.00 on 22 April.

At this time the 46^th Division attacked on the IX Corps' front and created a gap sufficiently large for Major General C. F. Keightley’s 6^th Armoured Division to pass through by the fall of night. The 6^th Armoured Division was followed by Major General R. Briggs’s 1^st Armoured Division, striking to the east for the next two days. However, the British armoured thrust was not rapid enough to prevent the Axis forces from creating a strong anti-tank screen, which then halted the British armour’s progress. Even so, the drive had been enough to draw the Axis armoured reserve to the south, away from the central front. Seeing that further progress was unlikely, Anderson withdrew the 6^th Armoured Division and much of the 46^th Division into reserve.

The attack of the V Corps was committed during the evening of 22 April, followed in the early hours of the next day by that of the US II Corps. The fighting on the V Corps� front against the Division 'Hermann Göring', 334^th Division and Generalmajor Hans-Karl Freiherr von Esebeck’s (from 13 May Oberst Max von Herff’s) 15^th Panzerdivision, and it required eight days for Major General W. E. Clutterbuck’s 1^st Division, Hawkesworthï's 4^th Division and Evelegh’s 78^th Division, supported by tanks and heavy artillery concentrations, to penetrate 6 miles (10 km) and capture most of the Axis defensive positions. The casualties on each side were heavy, but Anderson believed that a breakthrough was imminent.

On 30 April it had become clear to Alexander and Montgomery that the 8^th Army’s attack to the north from Enfidaville into terrain which was both difficult and strongly held would gain little success. Alexander therefore gave Montgomery a holding task and transferred Major General G. W. E. J. Erskine’s 7^th Armoured Division, Major General F. I. S. Tuker’s Indian 4^th Division and Brigadier G. H. Gilmore’s 201^st Guards Brigade from the 8^th Army to the 1^st Army, in which they joined the 1^st Armoured Division, which had been transferred before the main offensive. These movements had been completed by the night of 5 May. Anderson had arranged for a concentration of dummy tanks near Bou Arada on the IX Corps' front to draw the attention of the Axis forces and thereby help to conceal the advent of the 7^th Armoured Division in the Medjez el Bab sector.

In the event, the British did achieve a considerable measure of success, and the Axis forces suffered a major surprise about the size of the British armoured force as this was committed. Known as 'Strike', the final assault was launched at 03.30 on 6 May by the IX Corps, now commanded by Lieutenant General B. G. Horrocks in place of Crocker, who had been wounded. The V Corps had made a preliminary attack on 5 May to capture high ground and secure IX Corps' left flank. The British 4^th and Indian 4^th Divisions, concentrated on a narrow front and supported by massed artillery, pierced the Axis defences so that the 6^th and 7^th Armoured Divisions could pass through. On 7 May British armour entered Tunis, and US infantry of the II Corps, which had continued its advance in the north, entered Bizerte. Six days later the last Axis resistance in Africa ended on the Cap Bon peninsula, some 240,000 German and Italian troops becoming prisoners and very large quantities of matériel falling into Allied hands.