Simpson was 28 and had played 29 Tests without a hundred — the longest century-less stretch by any specialist batsman in Test history at the time. He had, however, scored centuries in three of the previous four Australian summers' Sheffield Shield finals; the question was when, not whether.
The answer came at Old Trafford. Simpson won the toss, batted, and sent in Bill Lawry to open with him. Lawry made 106 and they put on 201 for the first wicket. Simpson reached 100 in 415 minutes — slow even by his standards — and 200 in 590. He was 311 not out in his second day at the crease, then was bowled by Tom Cartwright shortly before lunch on the third day, having added 111 more runs in three hours after his overnight 265.
The innings was widely criticised in the English press for its tempo. Simpson's defence — that with the Ashes 1-0 to Australia and two Tests remaining, the only objective was to ensure England could not win — became the definitive statement of mid-1960s Test pragmatism. Australia totalled 656 for 8 declared. England responded with 611 (Barrington 256, Dexter 174). The match was drawn after exactly the four days Simpson had wanted to bat himself out of the firing line.
Simpson's 311 was the second-highest score by an Australian in Tests, behind only Bradman's 334 at Headingley in 1930. It was also the slowest Test triple century to that point. England's Geoff Boycott later cited it as the model for his own 1967 246 — a comparison that did Simpson no favours when the press attacked Boycott two years on.