The incident remains vividly etched in memory, although it was 15 years ago that I sat in my living room in Boston, monitoring the British Open from Royal Birkdale. Hale Irwin, the bespectacled former footballer from Colorado, had just missed a makeable putt, and, in his disgust, reached across the cup to tap the ball, which sat no more than an inch or two away, into the hole. What happened next occurred in the blink of an eye, but it was an instant all too familiar to anyone who has played golf.

Probably because he was holding his putter in one hand, Irwin's cursory swipe at the ball missed it altogether. Nearly, but not quite, in the same motion, Irwin recovered and this time nudged the ball into the hole.

Like millions of others, I saw it right away, although the television commentators did not. A few minutes later Irwin's revised score was announced, and was accompanied by endless replays of the misguided stroke. Irwin, ever the consummate professional, had immediately called the infraction on himself before leaving the green.

Golf is one of few sports where this happens. In many instances the player is left to be the sole arbiter of his intent, with his conscience left to determine the figure that is recorded on his scorecard.

History will record that in last weekend's 127th British Open, 22-year-old Tiger Woods came roaring down the stretch with three birdies over the final four holes to come up one stroke short of joining the man he calls his "big brother", Mark O'Meara, and Brian Watts in a play-off.

It is probably just as well he did. Had Tiger's stupendous, if somewhat tardy, charge resulted in victory, the laws of physics involved in his handling of the first green in Sunday's final round would have been subjected to even more scrutiny than they already have been.

As it turned out, Woods's official score of 281 will stand, but only he knows if it was the correct one. Tiger began the final round ignominiously enough, with a three-putt bogey that may well have been more than that.

After his second putt from 18 feet came to rest a few inches behind the hole, Woods walked up and, in disgust, knocked the ball into the cup. He stubbed the attempt, clipping the ground with his putter, and while he continued his forward motion, it appeared to come after the slightest, barely perceptible hesitation.

This left him facing at least two possible penalties. The most obvious was that the imprudent swipe at the ball might have counted as two strokes instead of one. The other is that if he did indeed stop his motion, and then "raked" the ball into the hole, he has not to this day legally finished playing number one, and might consequently have been disqualified.

Both of the above suggestions assume that Tiger would have to call the penalty on himself, or the R & A Rules Committee, which oversees the British Open, would have had to produce irrefutable evidence of the misdeed. Neither happened, although the incident was sufficiently suspicious that Sir Michael Bonallack, the secretary of the R & A, immediately went off to a cabin to view televised replays - and was still reviewing them several holes later.

There is no penalty for scuffing the ground in the course of one's putting stroke, and if Woods's was, as he maintained it was, one continuous motion, then it was a legal stroke and his score was the proper one.

This, apparently, was Tiger's contention, although as Peter Alliss remarked on the BBC, "that's certainly not what it looked like".

The television network, as well as the sports desks of newspapers around the world, received numerous phone calls from couch-bound golfers calling into question Tiger's stroke. Although Bonallack and the chairman of the championship committee scrutinised the videotaped replays in an effort to discern the precise circumstances, they concluded there was no infringement. For the record, Woods maintained his innocence. "I just tapped it in, simple as that," he said. "Unfortunately, it was for five."

The episode brought to mind similar occurrences which have found their place in golfing lore. The first, most obviously, was Irwin's. While neither the scorer nor the television commentators picked up on it, Irwin immediately called a penalty stroke on himself. Another was by Tom Wargo at Olympia Fields in last year's US Senior Open. The temperamental Wargo, who did not exactly endear himself to his Irish hosts when he represented America in the PGA Cup at the K Club a half-dozen years ago, tried to backhand a ball into the hole, stubbed his putter, and stopped perceptibly on the way to knocking it into the hole. Wargo did not see it as an infringement but a review by the USGA Rules Committee established a definite infraction. Confronted with the evidence, Wargo reluctantly revised his score before signing his card.

The new British Open champion, O'Meara, faced similar scrutiny when television replays caught him mis-marking a ball in last year's Lancome Tournament in France. The evidence came in too late to alter the outcome, and O'Meara has steadfastly maintained that his error was an innocent mistake.

Short of administering a dose of truth serum, we have no choice but to accept O'Meara's explanation of l'affaire Lancome, just as we must now accept Woods's; in the end, only Tiger knows for sure what happened on the first green at Birkdale.

It should probably also be pointed out here that, although O'Meara's final round on Sunday was incident-free, his path to the Championship was eased considerably by an episode a day earlier that also set the Rules Committee scrambling for more than 30 minutes. When O'Meara hit his second shot - a driver - to the sixth, the ball veered to the right and into a clump of bushes. After an unsuccessful search he headed back down the fairway to play a second ball when his original was found. However, by the time he returned to the scene to play his third, the ball, a Top Flite Strata 91 imprinted with an "O" logo, had gone missing. A spectator, it developed, had picked it up and had it in his pocket.

The small army of rules officials was left to consider issues, which were resolved in O'Meara's favour, to wit: (a) that although the five-minute limit had been exceeded by the time he reconnected with the original, he could be given "reasonable" time to identify it; (b) that the interloper who stuck it in his jacket pocket had acted as an "outside agency".

After an agonising debate involving R & A rules officials, in the course of which he and his playing partner lost three holes to the game playing in front of them, O'Meara retrieved the ball from the spectator who showed him the spot where he had found it. Efforts to replace the ball exactly proved unsuccessful and so the next step was to drop the ball without penalty. After his first drop rolled more than two club-lengths from the hole, and his second rolled nearer the hole, O'Meara was allowed to place the ball in a trampled-down lie, from whence he knocked it on the green. He two-putted for a bogey five.

"If that had happened in somebody's member-guest back home," remarked the dean of American golf writers, Dan Jenkins, "there would have been a fist-fight".

"It was," conceded O'Meara, "a tremendous break". And O'Meara was quick to acknowledge as much when he said to R & A rules secretary David Rickman: "Just tell me what to do and I'll do it."

Indeed. Had O'Meara made the seven or eight he forthrightly admitted he could easily have made on the hole, Brian Watts, or even Tiger Woods, might be the reigning British Open champion.