1992- Baron Stewartby of Portmoak
1988-9 Minister of State for the Northern Ireland Office
1987-8 Minister of State for the Armed Forces
1983-7 Economic Secretary to the Treasury
1983 Under-Secretary of State for Defence Procurement
1983-92 Member of Parliament for North Hertfordshire
1979-83 Personal Private Secretary to the Chancellor of the Exchequer
1974-83 Member of Parliament for Hitchin
1971-83 Director, Brown, Shipley & Co.
2008- Honorary Keeper of Medieval Coins, Fitzwilliam Museum
1996 Medal of the Royal Numismatic Society
1994- Honorary Fellow, Jesus College Cambridge
1986- Fellow of the Royal Society of Edinburgh
1981- Fellow of the British Academy
1978 LittD, Jesus College Cambridge
1972 Royal Naval Reserve Decoration
1971 Stanford Saltus Gold Medal of the British Numismatic Society
Also Fellow of the Society of Antiquaries, Fellow of the Society of Antiquaries of Scotland, Fellow of the Royal Numismatic Society, etc.
English Coins, 1180-1551 (London, 2009)
A New History of the Royal Mint, with C. E. Challis and others (London, 1992)
As Ian Stewart:
Coinage in Tenth-Century England, with C. E. Blunt and C. S. S. Lyon (London, 1989)
Studies in Numismatic Method, ed with C. N. L. Brooke and others (London, 1983)
Scottish Mints (London, 1971)
The Scottish Coinage (London, 1955; 2nd edn 1967)