Born in
Dunsley,
Kinver,
Staffordshire, to Robert Airlie Duff and Marjorie Catherine Duff (née Rust), Duff was educated at
Radley College and
Lincoln College, Oxford, where he played for OUCC for three years from 1959 to 1961. His early cricket at Radley was under the leadership of
Ted Dexter. Duff commented that his most distinguished feat on the cricket field was that in his first year in the XI at Radley, he drove Sir George (Gubby) Allen to retirement in 1954. Allen returned from Radley College to
Lord's announcing his total retirement having just been caught and bowled for nought off a full toss by a boy at Radley with a treble voice. Duff made his first-class debut in June 1959 for Oxford University against
Essex, and had a decent game in a heavy defeat, scoring 53 and 4 with the bat and taking three wickets (the first of these being that of
Gordon Barker). A few days later he made 40 against
Free Foresters, then later that same month hit 55
not out against
Warwickshire. He had two games for Worcestershire's Second XI at the end of the season, and hit seventies in each one. In 1960 Duff took 22 wickets, the most he managed in any season, including 4–24 for Oxford against
Nottinghamshire. He played for the university for the first half of the season, then in July and early August appeared in four
County Championship games for Worcestershire; in one of these, again against Nottinghamshire, he hit an unbeaten 50. He also turned out for
Marylebone Cricket Club (MCC) against
Ireland at the end of the season. 1961 proved a mixed season for Duff: in 24 innings he managed 223 runs at an
average of 11.15, although with the ball he was more successful in claiming 15 wickets
at 27.46. His first-class appearances were mostly for Oxford, but there were two matches (his last) for Worcestershire. He played not at all in 1962 and made only a single second-team appearance against
Gloucestershire II in 1963 (although he did take eight wickets in that game). Duff returned to first-class cricket in 1964 with his only game for
Free Foresters, against his former university. After that he was to play only three more first-class matches, all for MCC against Ireland: one later in 1964, one in 1966 and one in 1968. He also played a considerable amount of
club cricket, and accompanied MCC on many minor tours. As a club cricketer he was a member of and played for the Free Foresters,
IZ, Arabs, Cryptics, Gentlemen of Worcestershire, Sussex Martlets and Radley Rangers. ==MCC tours==