As the ball hung in the air, you almost knew what was coming. Travis Head had been the key wicket all series, and England desperately needed to see the back of him. So Will Jacks dropped it. Of course he did. It has been that kind of game, and that kind of tour.

If sadism’s your thing, and especially if you’re Australian, the SCG on the third day of the fifth Ashes Test was the place to be. England began this Test hoping for the sticking plaster of a 3–2 defeat, but by stumps were contemplating a salt-in-the-wound scoreline of 4–1.

And if that happens, it will be hard for the ECB to justify their basic impulse, which is to avoid the kind of sweeping changes that so often follow an Ashes trip. Managing director Rob Key and head coach Brendon McCullum, to say nothing of the backroom staff, could face a nervous few weeks.

The ECB’s stance felt even less secure on a day when England did what sides tend to do at the end of a long trip, and fell apart at the seams.

The Jacks clanger was bad enough, reminding everyone that dropped catches tend to be a barometer of a team’s state of mind, and emphasising the absence of a fielding coach – a remarkable oversight that says little for pre-tour planning and plenty about the dressing room’s looseness.

But as the irrepressible Head turned his reprieve on 121 into a punishing 163, taking his series haul to exactly 600, and Steve Smith inevitably compiled his 13th Ashes hundred, England’s disintegration was everywhere you looked.

Their decision making, both big-picture and small-detail, was badly exposed. It made little sense, for instance, that Ben Stokes should use up his remaining two reviews trying to prise nightwatchman Michael Neser from the crease.

Yet that is what he did in his desperation to turn an erroneous caught-behind appeal, then a marginal lbw call, in England’s favour.

Most painful of all, perhaps, was the fate of Matthew Potts, who had been taken apart on the second evening by Head, and spent the third day powerless to change the narrative.

By stumps, he was nursing an analysis of 25–1–141–0 in which the greatest surprise was the maiden. Only five seamers in English Test history had gone wicketless while conceding more runs in an innings, and none had an economy-rate remotely as bad as Potts’s 5.64.

But if a cruel case could be made for saying this was the most hapless display by any English quick, then the bowler himself also feels like a victim of fly-by-night planning.

Between his last county championship game for Durham in late September and his appearance here, he had bowled only 58 overs of one sort or another. Not one of them was in a first-class match, and not one has been delivered since November 29. 

He has spent four-fifths of the business end of this tour either in the nets or delivering drinks.

Yet here he was, expected to operate at his best in a game which, despite the surrender of the Ashes, England were desperate to win. It is fair enough, on the evidence here, to ask whether Potts really is Test-class.

But it is also fair to ask whether he has been given the best chance to succeed, or indeed any chance at all.

Given the fragile nature of the bowling attack that arrived in Australia, a concern borne out by the tour-ending injuries to Mark Wood, Jofra Archer and Gus Atkinson, it can’t have been beyond the wit of the management to ensure Potts was better prepared for a potential appearance.

Instead, when he wasn’t dropping short and wide, as he did repeatedly in his first spell to Head, he was overpitching, as if this were Chester-le-Street in May and the surface would do the rest.

By the end of an exhausting day on which Australia turned 166 for two into 518 for seven, and Smith overtook Jack Hobbs to become Ashes cricket’s second-leading run-scorer behind Don Bradman, poor Potts was employed as the battering ram, bowling short down the leg side. He might as well have been waving the white flag.

The speed with which Stokes has turned to the short-ball plan in this series has been another indictment of the set-up.

During the third Test in Adelaide, fast-bowling coach David Saker pointed out that his philosophy has remained unchanged from the days when he worked with Jimmy Anderson and Stuart Broad: aim for the top of off stump, and you’ll more often than not be fine.

Has anyone been listening? Apparently not. Instead, the waywardness of England’s quicks has caused the captain to lose faith, and the injury to Archer – who went at barely three an over during the first three Tests – has robbed him of his safety valve.

Short-pitched bowling places less emphasis on accuracy, but it also hastens exhaustion and, as Australia piled on 141 in an extended evening session, it was clear England had neither the control to keep the runs down nor the energy to take wickets.

Brydon Carse finished the day with three for 108 from 23 overs, which summed up an erratic tour.

No England seamer since Jimmy Anderson in 2010-11 has picked up more than his 22 wickets on an Ashes tour, and Carse is the only English quick, along with Stokes, to play in every game.

But he has gone at 4.68 an over, and lacks the skills to make a regular impact with the new ball. As much as Potts, his Durham team-mate, Carse has been an emblem of a trip which has proved a failure of imagination and execution.