This was the British tactical deception plan in support of the 'Pugilist-Gallop' assault on the Mareth Line defences, just inside the Tunisian border with Libya, by Lieutenant General Sir Bernard Montgomery’s British 8th Army (9/20 March 1943).
The plan was the brainchild of Lieutenant Colonel David Strangeways, latterly of Colonel Dudley W. Clarke’s 'A' Force Middle Eastern deception organisation, and who with his small team reached the headquarters of General the Hon. Sir Harold Alexander, commander-in-chief. Middle East, on 17 February, two days before Alexander’s Allied 18th Amy Group was brought into existence. Strangeways quickly assessed the Tunisian front and prepared his first deception plan, which was approved on 9 March.
This 'Lochiel' (i) supported 8th Army’s attack on the Mareth Line, and was in essence a development of the concept embodied in 'Windscreen', which Clarke had operated in connection with Montgomery’s 'Guillotine' (ii) advance to Tripoli. In it, double agents had reported that there would be a landing at Tripoli in Rommel’s rear because administrative difficulties had slowed the 8th Army. The 'story' promulgated by 'Lochiel' (i) was that while the 8th Army paused to allow supplies to reach it before attempting to break though the Mareth Line, US and Free French forces were to attack farther to the north in the direction of Kairouan, supported by a diversionary landing in the Gulf of Gabès.