Sir Iain Maxwell Stewart (1916–1985) LLD (Strathclyde), BSc, MINA, MINE, MIMEch.E was a Scottish industrialist with a strong interest in modernising industrial relations.

[5] With its headquarters in Helen Street, Govan, the pioneering heating, cooling and ventilating Thermotank Ltd group of companies in Glasgow soon had branches and agencies world-wide.

[8] Stewart was the seventh of 26 signatories ("from the churches, the boardrooms, the trade unions and the teaching profession") of those who met in Marlow over 15 months between November 1961 and February 1963 to discuss social and industrial relations.

[9] It talked about an ethical approach to business and social issues, stating that industry had five responsibilities, to employees, to shareholders, to consumers, to local community and to the nation.

"[11] Sir Iain M Stewart gave the Institution of Engineers and Shipbuilders the substantial sum of £10,000 to underwrite the aptly-named Marlow Lectures, an important event in Scotland's calendar.

[26] He also served as a director of many other companies including Babcock & Wilcox, Eagle Star Insurance, British Caledonian Airways of which he became deputy-chairman, retiring in 1984 one year before his death, British Airways, National Commercial Bank of Scotland, Royal Bank of Scotland, Dorchester Hotel owned by the family of Sir Robert McAlpine, Radio Clyde, and Lyle Shipping Co Ltd of which he became chairman.