 After working as a management consultant, he joined a major food manufacturing and distribution company and became managing director and chairman.He was a Lloyd's underwriter specialising in maritime and aviation reinsurance.Stainton was Member of Parliament for Sudbury and Woodbridge from a 1963 by-election until the 1983 general election, when the seat was abolished by boundary changes; he failed to win selection in either of its successor seats, South Suffolk and Suffolk Coastal.