 Two years later he joined the 2nd Volunteer Battalion, Manchester Regiment.In 1910, Cawley entered the British House of Commons for Heywood, and a year later he was appointed Parliamentary Private Secretary to the Home Secretary Reginald McKenna.On the outbreak of World war I in 1914 he served with his Territorial Force battalion (now the 6th Battalion, Manchester Regiment and became aide de camp to Major-General William Douglas, the officer commanding 42nd (East Lancashire) Division.