'Imperator' was a British unrealised plan to take and hold Boulogne or a similar coastal port in the northern part of German-occupied France by means of amphibious assault, and then to launch a large mobile force toward Paris before falling back and being evacuated from a different port (summer 1942).

The plan was devised in response to a request from the USSR for aid at the time of Germany’s 'Blau' offensives in the summer of 1942, and was designed to force the Germans to draw from the Eastern Front a sizeable proportion of their air strength to bolster the very limited forces that had been left in western Europe by the preparations for and execution of 'Barbarossa'.

Given the strategic and operational impracticality of the entire undertaking, it was fortunate for the British and commonwealth forces which would have been used, the plan was abandoned well before its scheduled implementation in August 1942.