When this fleet failed to put Motion to sea , the Rochefort squadron , under Contre-Admiral Zacharie Allemand , went on an extended Expansion raiding cruise Attack across the Atlantic , both to intercept Attack British trade left Departing lightly defended Defending by the concentration of British forces Causation in European waters and with the intention of eventually combining Creating with the French Mediterranean Fleet then blockaded Besieging in Spanish harbours .

Departing Departing from Brest on 13 December 1805 , it was 12 days before the Admiralty in London were aware of the French movements , by which time the French squadrons were deep in the Atlantic , one under Vice-Admiral Corentin-Urbain Leissègues intending to cruise Self_motion in the Caribbean and the other , under Contre-Admiral Jean-Baptiste Willaumez , sailing Self_motion for the South Atlantic .

Other squadrons already at sea became Becoming embroiled in the campaign : a smaller squadron that had been raiding Attack the African coast under Commodore Jean-Marthe-Adrien L'Hermite since August 1805 provided Supply a diversion to the major campaign but failed Agree_or_refuse_to_act to draw Removing off significant British forces Military_operation , while the remnants of a French squadron under Contre-Admiral Charles-Alexandre Durand Linois that had been operating Being_in_operation in the Indian Ocean since 1803 was intercepted Preventing_or_letting and defeated Conquering by Warren in March , after a chance encounter on its journey back to France .

The British squadron consisted of seven ships of the line accompanied by associated frigates , led Conquering by Rear-Admiral Sir John Borlase Warren , were tasked Request with hunting Military_operation down and destroying Destroying the French squadron of Contre-Admiral Jean-Baptiste Willaumez , which had departed Departing Brest for raiding Attack operations in the South Atlantic in December 1805 , at the start of the Atlantic campaign Military_operation of 1806 .

The French force consisted of one ship of the line and one frigate , all that remained of Contre-Admiral Charles-Alexandre Durand Linois ' squadron that had sailed Self_motion for the Indian Ocean in March 1803 during the Peace of Amiens .