 Hard steaming during this service led to her developing serious machinery problems.At the beginning of the First World War, "Formidable" and the 5th Battle Squadron were based at Portland and assigned to the Channel Fleet to defend the English Channel.After covering the safe transportation of the British Expeditionary Force to France in August 1914, "Formidable" took part in the transportation of the Portsmouth Marine Battalion to Ostend on 25 August.