As his older half brother Pat (Spike) Hughes, wrote[4] of a visit to Glen Riddle in 1933: "...at 4 years and a few months, Iain was already passionately interested in seeing how things worked, and showed a typical lack of concern for what came out of a loudspeaker, so long as he could make out why it came out at all.

The Gunn family returned to England in 1934 when Jack was appointed Professor of Egyptology at the University of Oxford.

Ian was educated in England, with the exception of two years spent at Solebury School, Pennsylvania as a wartime evacuee.

In 1953 he returned to RRE in Malvern, taking up a post as a Junior Government Research Fellow, where he worked on avalanche injection, carrier accumulation and related topics in experimental semiconductor physics.

He first moved to Canada in 1956, to take up an Assistant Professorship at the University of British Columbia,[8] before going to the United States in 1959 to work at IBM's Thomas J. Watson Research Center at Yorktown Heights, New York.

Gunn stayed with IBM for the rest of his career, spending time on the Corporate Technology Committee, and at the San Jose research lab in California, before returning to Yorktown.

In 1962, while working for IBM, he discovered the Gunn effect[9] based upon his refusal to accept inconsistent experimental results in Gallium arsenide as simply "noise".

[12] Alan Chynoweth, of Bell Telephone Laboratories, showed in June 1965 that only a transferred-electron mechanism could explain the experimental results.

Gunn stopped working on semiconductor physics in 1972, and pursued a number of different interests in his role as IBM Fellow.

He spent nearly three years developing an APL computer model of a computer-controlled car, which showed that fuel consumption could be halved.

[13] This was part of a joint effort with John Cocke, who made major contributions to computer architecture, and R. A. Toupin in a study, that used computer simulation to investigate regenerative braking, a high-pressure hydraulic system to store energy, and several other topics that are now quite common practice.

He was the first to suggest non-linear measurements to detect incipient opens, and this led to a production tool which effectively solved the problem.

He married Freda Pilcher (1924–1975) on the Saturday of August Bank holiday, raced his International Norton at Blandford, Dorset, on the Monday, before continuing on to their honeymoon.

He had no bikes while at UBC, but bought a Ducati 200 shortly after moving to IBM, and started racing with Association of American Motorcycle Road Racers (AAMRR).

He qualified in the front half of the field, and ran as high as 10th, but retired with a minor mechanical failure.

Gunn also owned a few classic cars, including a 1930 supercharged 1750 SS Alfa, originally raced at Brooklands by George Eyston and a 1971Datsun 240Z.

After Gunn's death in 2008, his three daughters sold the car to noted Ferrari collector Andreas Mohringer of Austria.

After refurbishment and then display at the Pebble Beach concourse event, it was shipped back to Paul Russell's shop in New England.