'Bigamy' (i) was a British attack by 'X' Force (L Detachment of the 1^st Special Air Service, the S1 and S2 patrols of the Long Range Desert Group, and a detachment of Royal Marines) on the Axis positions round Benghazi in the Cyrenaica eastern part of Libya within 'Agreement', for which it was a deception, and often known wrongly as 'Snowdrop' (13 September 1942).

Lieutenant Colonel A. D. Stirling’s 'X' Force moved on Benghazi from Kufra oasis round the southern edge of the Great Sand Sea with the tasks of blocking the inner harbour, sinking all the Axis shipping in the harbour, and destroying all the Axis oil installations (storage and pumping) before falling back to Jalo oasis, which was to have been captured by 'Z' Force (a detachment of the Sudan Defence Force with one patrol of the LRDG), from which it would continue harassing operations for another three weeks.

The operation was a failure as 'X' Force was detected at a roadblock en route to its objective by an Italian reconnaissance unit, and Stirling therefore decided to withdraw to Kufra oasis rather than Jalo oasis. During the withdrawal German aircraft picked off nearly 70 of the force’s vehicles as they tried to cross barren terrain that offered no chance of concealment. The survivors were re-formed as the 1^st Special Air Service Regiment.