This was a British deception plan within ‘Zeppelin’ (ii) suggesting that an amphibious attack was to be made in the area of Marseille on the south coast of German-occupied France (May/July 1944).
The plan was the western Mediterranean element of the fourth phase of 'Zeppelin' (ii) and thus a complement to 'Turpitude' and related to 'Ironside II', and more specifically created the 'story' that the US 7th Army was about to land on the south coast of France in the area of Narbonne and then exploit inland to Toulouse. The 'story' was based on a 7th Army strength of one notional US corps, one real French corps and one notional French corps with four real and eight notional divisions.
More specifically, therefore, after it had been decided that 'Anvil' (later 'Dragoon') would take place in August, it was settled that the task to by undertaken by Colonel Dudley W. Clarke’s 'A' Force in the western Mediterranean would be to persuade the Germans to hold significant reserves in the south of France for between 25 and 30 days from D-5 of 'Neptune' (iii), the amphibious landing element of 'Overlord'. As decided during the first week of May, 'Vendetta' was to be based on the story of a landing by Lieutenant General Alexander McC. Patch’s US 7th Army in the area of Sète and Agde in the south-western part of France’s Mediterranean coast (a location chosen specifically to be as far as possible from the selected 'Anvil' landing area) for a inland advance to seize the Carcassonne gap and then to exploit toward Toulouse and Bordeaux. The US 7th Army was to be composed largely of notional formations spearheaded by Major General Terry de la M. Allen’s notional XXXI Corps.
The implementation of 'Vendetta' was was hampered to a modest degree by a lack of sufficient resources. Nearly all of its formations were imaginary, but the genuine US 91st Division was then deployed to Italy; one of the genuine French formations, the 9th Division d’Infanterie Coloniale, was diverted to the occupation of Elba; most of the genuine landing craft were in England for 'Neptune' (iii); and there were not even spare genuine anti-aircraft guns.
'Vendetta' started early in May with much activity, such as smoke screens, dummy landing craft, dummy anti-aircraft protection and stockpiling of supplies, at Bône, Ferryville and Oran, the logical French North African ports from which the operation would be launched. Maps and photographs of the target area were issued, instruction in basic French was offered to the troops, civil affairs directives were drafted, and Allied diplomats asked the Spanish authorities to make available at Barcelona facilities for landing non-military supplies and evacuating wounded.
A major amphibious assault exercise was held between 9 and 11 June with 60 naval vessels including the British fleet carriers Indomitable and Victorious, which were passing through the Mediterranean on their way to the Pacific. Some 13,000 men and 2,000 vehicles of the 91st Division were actually put afloat at Oran and kept at sea for three days, while the air was filled with appropriate radio traffic, heavy bombers ranged far up the Rhône river, and fighters struck targets in the area if Sète. On 11 June the border between Algeria and Spanish Morocco was closed, and the cipher and diplomatic bag privileges of neutral diplomats were suspended.
But as the 91st Division was transported to Italy, the 9ème Division d’Infanterie Coloniale became involved in 'Brassard' on Elba, and the British carriers continued on their passages to the Far East, the pretence of 'Vendetta' could not be maintained indefinitely. From 24 June, therefore, double agents began to disseminate the 'story' that because reconnaissance had established that the Germans had not moved their forces in southern France to the Normandy bridgehead, General Sir Henry Maitland Wilson, the Supreme Allied Commander Mediterranean, had decided to postpone the attack. The border was reopened on 6 July and on 14 July the Spanish authorities were advised that it seemed unlikely that the Allies would need the requested humanitarian facilities.