'Lifebelt' was an Allied unrealised plan to use military force or, if possible, to occupy the Portuguese possessions in the Atlantic Ocean, namely the Azores, Madeira and Cape Verde island groups, in order to prevent their seizure and use by the Germans as bases for maritime aircraft and U-boats involved in the campaign against Allied shipping in this theatre, and to provide air bases and escort force refuelling points for the Allied units in the Atlantic war (June 1943).

The deception supporting this operation was 'Dummer'.