After serving as Shadow Secretary of State from 1962, he became Secretary of State for Scotland in 1964 under Harold Wilson. The Conservatives held government from 1970 to 1974, when Ross resumed his position until he lost office when Wilson resigned in 1976. During his tenure he was responsible for the creation of the Highlands and Islands Development Board and the Scottish Development Agency, the forerunners of Highlands and Islands Enterprise and Scottish Enterprise respectively. Ross campaigned for a "No" vote in the 1975 referendum on British membership of the EEC. He was also a firm unionist, in favour of Scotland and Northern Ireland remaining in the United Kingdom, and opposed devolution. Journalist Andrew Marr has called him "a stern-faced and authoritarian Presbyterian conservative who ran the country like a personal fiefdom for Harold Wilson". Ross coined the term 'Tartan Tories' to describe the members of the Scottish National Party, whom he very much disliked; he was himself nicknamed "the hammer of the Nats" for his many attacks on them.