'Patent' was a British deception operation in the Middle East designed to ease the pressure on supply convoys to Malta by the supposed threat of an invasion of Greece in the Dodecanese islands group, and then Crete (June/July 1942).

During June and July 1942, and despite the fighting of the period known as 'The Flap' and involving the British defeat in the Battle of Gazala, the loss of Tobruk, the Axis advance to El Alamein and the 1^st Battle of El Alamein, Colonel Dudley W. Clarke’s British 'A' Force deception organisation launched a pair of strategic operations whose nature and success established the pattern for maintaining a threat to the Axis forces and plans in the eastern Mediterranean.

The first of the deception undertakings was 'Patent', which followed on the threat to the Dodecanese islands group which had first been mounted in April in connection with the 'Ironclad' invasion of Vichy French Madagascar. 'Ultra' decrypts of intercepted Axis signals traffic revealed that Germany and Italy were still very concerned about the Dodecanese islands group, and early in June 'A' Force was instructed to play on these fears as a means, it was hoped, of diverting Axis attention from 'Harpoon' (ii) and then 'Vigorous', which were a pair very important supply convoys to Malta. 'Patent' was implemented mainly through the standard intelligence channels of the Security Intelligence, Middle East organisation, but, in the first use of what became a standard plot, when the assault ships for the notional assault were departing toward the Dodecanese islands group, all communications and travel from Egypt, Palestine, Syria and Iraq were suspended for two days.

After the 'Harpoon' (ii) convoy had reached Malta, despite heavy losses, it was appreciated that 'Patent' had indeed succeeded in creating alarm throughout the Aegean Sea area and was maintained with the 'story' that the Axis offensive through the eastern part of the Western Desert had forced a last-minute postponement of the assault on the Dodecanese islands group.

Early in July, the focus of 'Patent' was moved westward to Crete in the hope that most of the island’s German and Italian garrison forces would be kept there rather than used to reinforce the Axis forces in North Africa. This hope proved illusory, but there were nonetheless reasons to believe that the basic idea was sound and could be useful in the longer terms, and this paved the way, late in July, to 'Rayon', the other of the strategic deception efforts on his period in the eastern part of the Mediterranean.