From the early to mid-1970s, Cable served as First Secretary under Hugh Carless in the Latin American department of the Foreign Office. He was involved in a CBI trade mission to South America at this time, engaging in six months of commercial diplomacy. In the late 1970s, he was special adviser to John Smith when the latter was Trade Secretary. He was an adviser to the UK Government and then to the Commonwealth Secretary-General Shridath "Sonny" Ramphal in the 1970s and 1980s.