England's captain is slipping down the charts quicker than a boy band's single. How long ago it seems since Sydney in the early part of 2003. He had scored a coruscating 193 against Australia in the final Test, he was the player of the series and he was ranked as the No 1 batsman in the world.
Think of it: an Englishman in a heavily beaten team still trying to find their way, and he was the best batsman on the planet. It was a status he deserved, too. He was rigorous in method, straight, orthodox and elegant. His cover drive was as beautiful as it was effective.
But yesterday at Edgbaston, Vaughan's form appeared to have reached a nadir. He was castled by Brett Lee. The ball was fast and straight, as you would expect, but Vaughan was going nowhere in addressing it. Before this match he had slipped to No 28 in the world rankings, and he could now be out of the top 30.
There was hardly a single decent aspect about the shot to the ball that bowled him yesterday. He began with a forward press, then became stuck in the crease, as if half-expecting low bounce. To compound everything he brought his bat down crookedly and the ball burst through that creakily constructed defence. You could over-analyse it, but you did not need to have the most rudimentary coaching badge to realise that the shot was just plain bloody awful, and if the ball kept a tad low it was all he deserved for playing it like that.
It was a bad way to go and it was a bad moment for England. Vaughan has never been the player he was in Australia since he became captain three Test matches later. He is not the first captain whose form has been brought low by the cares of leadership, and nor is he the first to deny it.
Indeed, Vaughan has said time and again that his form has held up pretty well, and when pressed will say that he has averaged 40 as captain. This sounds pretty good, and the spiral has not all been downward. But in 52 innings as captain his batting average is 35.53, just about on the correct side of acceptable. Take matches against Bangladesh out of that equation and it slips to 30.83, the wrong side of acceptability.
There is no easy way round this. Being captain of England is a tough job. Vaughan, who has a wonderfully impressive sense of perspective, is nonchalantly categoric in insisting that plenty of people do jobs that are more significant.
He would seem to have an ideal temperament for the rigours of office. He is not a heart-on-sleeve merchant as was his predecessor, Nasser Hussain, he is not as plainly relaxed in approach as was, say, David Gower. There is little that is emotive about Vaughan. When he speaks to the press, even before this Ashes series, the biggest of his life, perhaps especially before this Ashes series, he might as well be dictating a shopping list.
But it is affecting him. How otherwise to explain the dip that, in truth, is becoming something akin to the Grand Canyon. Maybe it would help if Vaughan conceded the point. To be repaired, you first have to realise that something needs fixing. Three times in the past year, Vaughan has been for week-long batting clinics with the England coach, Duncan Fletcher. If there was nothing wrong he would not need the clinic.
Last year, he responded after the first with two hundreds in the Lord's Test against West Indies; after the second, in South Africa in January he made a gritty, unbeaten 82 and 54 in the sensational Test victory against South Africa in Johannesburg. The third session has not been as effective, resulting in 24 and a grotesque hook in the first innings and one run in two balls yesterday. Maybe he simply needs a longer period at the clinic each time.
Certainly, his figures since the beginning of the winter tour have been fairly unprepossessing. Apart from the two half-centuries at the Wanderers and a gimme hundred against Bangladesh at the start of this season he has had 13 other innings. In 11 of them he has failed to get beyond 24.
He has often looked tired and careworn. But it is a testimony to him that he has always managed to sound relaxed. His side are clearly devoted to him. In the field, he thinks quickly and astutely. He is not allowing his own form to affect his decision-making.
He is not one to dwell on it, let alone talk publicly about it. Vaughan's greatest friend in the team is Ashley Giles, who has shown his sensitive side this past week (and also, by the way, answered his critics in some style in Birmingham).
There is no question of England turning against Vaughan or beginning to doubt his qualities, a point that Giles put his finger on while discussing his own turmoil on Friday. "Everyone in the dressing room has had a rough time as well," he said. "We always back each other up."
And that is where Vaughan will draw the strength to carry on and surmount this lapse. He will probably never again bestride the cricket world as he did that winter of 2002-03. He thinks he can, but the longer this run goes the greater the technical flaws will become.
Maybe the real fault lay in the decision in the summer of 2004 to move him to No 3 in the order. He had been an opener all his career. Only when he first started with England did he bat in the middle order, but it was as an opener that he made his reputation. Along came Andrew Strauss when Vaughan was injured, and it seemed suddenly to be decided that the captain had been a No 3 all along. At present, that looks about six places too high.Reuse content