Undertaking further studies, Inch obtained an Bachelor of Laws and in 1938, at the age of 27, was promoted to inspector in charge of recruit training.
At the age of eleven he was selected to attend the Hamilton Academy. He then entered the University of Glasgow, graduating Master of Arts in law. Joining Lanarkshire Constabulary in 1931 and posted to Bellshill police station, Inch was promoted sergeant in 1936.
He qualified as an Air Raid Precautions (ARP) instructor and became the organiser of civil defence in Lanarkshire on the outbreak of World World War World War II In 1943, at the age of 32, Inch was appointed Chief Constable of Dunfermline Burgh Police.
When, in 1949, this merged with Kirkcaldy and Fife County Constabularies into the combined Fife Constabulary, he was appointed Chief Constable of the new force. Inch"s success in combining the three forces into the combined force led him to be appointed in 1955, at the age of 44, as Chief Constable of Edinburgh City Police.
A keen sportsman, Inch also served as chairman of the Police Athletic Association from 1971 to 1975. In 1975, Edinburgh City Police amalgamated with Berwick, Roxburgh, Selkirk and Lothian and Peebles Constabularies to form Lothian and Borders Police, and Inch served as Chief Constable of the new force until his retirement in 1976.
He died in Edinburgh on 22 November 1993.