After piloting flying boats in the Second World War, Monro became a farmer in his native Dumfriesshire. He became active in local test politics in the 1950s, and was elected as MP for Dumfries in 1964. He served as a Conservative whip and held three junior ministerial positions, twice in the Scottish Office and once as Minister for Sport in the Department for the Environment. He became a member of the House of Lords in 1997, after he stood down from the House of Commons. He was particularly concerned with Scottish and rural issues, the RAF, and sport, and was noted for his strong links with his constituency. He was in office at the time of the Lockerbie Disaster in 1988, which occurred in his constituency.
After he was demobbed in 1946, he became a farmer at Kirtlebridge near Lockerbie, although he also had other business interests. He remained a member of the Royal Auxiliary Air Force from 1947 to 1954. He was later an honorary Air Commodore from 1982 to 2000, and its honorary Inspector General from 1990 to 2000.
Monro married twice. He married Anne Welch in 1949. Their two sons joined the British Army. Seymour retired as a major-general; Hughie is a retired brigadier. Monro's first wife died in 1994; later that year, he married a second time, to Doris Kaestner, a friend of his first wife. Monro's grandson, Ander Monro, has played for the Canada national rugby union team.
Monro came under some criticism for opposing the visit of a South African Barbarians rugby team to the UK and a return visit by the British Lions rugby team the next year. He was dropped from the Government in 1981 in the wake of Mrs Thatcher's proposal that the British team pull out of the Moscow Olympics, receiving a consolatory knighthood that year.[2] In 1986, he suggested that the government bill the Kremlin in the amount of £1 million and provide the amount to Scottish farmers in compensation for losses to sheep herds caused by the Chernobyl nuclear disaster.
In 1988, a bomb exploded on Pan Am Flight 103, which crashed at Lockerbie, near his home. He was closely involved in the aftermath as the local constituency MP, and went out to Lockerbie with two other MPs. He was hailed by politicians of all political stripes for his compassion and caring; Scottish Labour MP Brian Wilson praised him as "a man who is truly a part of the community that he represents".[3]
He returned to the Scottish Office on 9 April 1992, but he was sacked from this position on 5 July 1995. He became a member of the Privy Council in 1995, and following his retirement as an MP, was made a life peer as Baron Monro of Langholm, of Westerkirk in Dumfries and Galloway on 6 November 1997.[4]
The number of Conservative MPs from Scotland declined from 24 when he was first elected an MP in 1964 to nil after the 1997 general election. A One Nation Conservative, he occasionally rebelled against the official party line, opposing the closing of British Steel Corporation's Ravenscraig steelworks, for example. One of his Labour Party opponents, Norman Hogg, dubbed him "the last of the decent Tories".[5]