As captain, he suffered a lack of support from Geoffrey Boycott, who had hoped to be appointed captain instead, and these tensions contributed to the downfall of Denness as a skipper. Boycott played in the first 6 Tests with Denness as captain, including the five matches in the 1–1 drawn series in the West Indies and the first Test of a 3–0 whitewash against India, during which Denness scored his first two Test centuries, but Boycott then refused to play under Denness and remained out of the Test team until 1977. After a 0–0 drawn three-match series against Pakistan at home in 1974, Boycott's boycott left England exposed in several matches against the fast bowling of Dennis Lillee and Jeff Thomson in the Ashes series in Australia in 1974-5. Denness dropped himself from the England team for the 4th Test at Sydney after scoring only 65 runs in 6 innings (6, 26, 2, 20, 8, 2) in the first three Tests, although he was selected again for the 5th Test in Adelaide after his replacement John Edrich was injured, and achieving his highest Test score of 188 at Melbourne in the 6th Test to win by an innings. The victory was little consolation, as Australia had already won four of the six matches in the series. While in Australia, Denness received an envelope that had been sent with the address "Mike Denness, cricketer". The letter inside read, "Should this reach you, the post office clearly thinks more of your ability than I do."