But those of us who were at Worcester College with Martin knew why he was so attached to it. Like many a great sportsman, he had his superstitions. When his batting was not going well then the old striped cap came out. It worked. The batting returned to its normal magnificence. Then the dark blue cap was re-assumed.
In college, Martin was universally liked. He was a quiet, modest man who was interested in the same things as the rest of us. At a college society meeting he talked about folk-music and folk-songs. He was not too grand for college games, and, if he were available, he would play in the college teams for cricket and rugby, at a time when they were far from strong. In one such match he hit five sixes in one over, against a visiting team that had not expected to encounter a Test batsman.
One evening Martin and I went to have dinner with some New Zealand friends who lived on the outskirts of Oxford. We suddenly realised that it was high time for us to leave if we were to be back in college before midnight, that being the rule. Our hostess telephoned for a taxi but was told none would be available for at least an hour.
With great presence of mind, she explained that it was Martin Donnelly, the Oxford cricket captain (this was in 1946), who needed the taxi. And, she added, if he were not back in Worcester College by midnight then he would be "gated" and unable to play. Her plea was dramatically successful. Within minutes a taxi had arrived and we were back in college with time to spare.
I bumped into our hostess a few years later. She told me that the taxi firm still had her on their priority list.