Designed to support Operation Crusader, a decoy convoy, GM 3, was assembled, in an attempt to divert Axis aircraft away from the land battle.
The freighters were to turn back after dark and return independently while the escort conducted a two day anti-submarine sweep.
Force K contributed to the deception by sailing westwards from Malta to simulate a rendezvous with GM 3, then reversing course overnight.
A second diversion force, as Operation Landmark, left Malta early on 21 November, feigning a voyage to Alexandria to escort four merchant ships.
B-Dienst (Observation Service) learnt from British naval signals Force K was at sea, so an Italian convoy and escorts were ordered to port rather than risk battle.