Operation Treatment (1942) was the intelligence element of the deception plan for the second battle of El Alamein, and focused on convincing the Germans that the offensive would start on 6 November, two weeks later than was planned (North African Campaign).
Operation Treatment was run by 'A Force', the Middle East deception force commanded by Colonel Dudley Clarke. He was already running Operation Cascade, an attempt to convince the Germans that the British had many more troops in the Middle East than was actually the case, and was experienced in deception. Montgomery wanted him to help convince the Germans that the upcoming desert offensive was expected to start on 6 November. 'Treatment' was run by Clarke, and by his deputy Lieutenant Colonel Noël Wild, who took over when Clarke was called away to help plan Operation Torch in October.
Operation Treatment used the intelligence network controlled by the British around the eastern Mediterranean. Key to this was the Cheese network, a fictitious network of spies that had been in use for some time. The various intelligence networks available to Wild were used to spread the idea that Montgomery wasn't planning any major offensive against Rommel, but was instead worried about a possible German advance through the Caucasus, which would threaten Iran and the Persian Gulf. This had been a genuine concern earlier in the year, and although the Germans were increasingly bogged down around Stalingrad it was still a convincing story.
A second story was that the British were planning to invade Crete. This story had some impact, and on 23 September Hitler ordered the garrison to be reinforced. He repeated this order on 21 October, although Rommel's army at El Alamein still contained paratroop battalions that had recently moved from Crete.
A third plan was the creation of a high level conference, to be held in Tehran on 26 October. The commander-in-chief in the Middle East (General Alexander), the commander of the Persia and Iraq force and the Commander-in-Chief in India were all meant to take part. While the high command was in conference, lower level officers were said to be free to book leave, and a number of hotel reservations were made in their names, to cover the same period.
The second part of the deception plan was Operation Bertram, which covered activity on the ground in the Western Desert. Between them these two plans probably confused the Germans. Rommel was absent in Germany when Montgomery began the Second Battle of El Alamein on 23 October 1942, and he had split his armour, with half in the north and half in the south. The success of these operations has perhaps been overshadowed by the more famous Operation Fortitude, the deception plan for the D-Day invasions, but the experience gained in North Africa played a major part in the success of those plans.