For a moment, Ollie Pope stood rooted to the spot. He was probably trying to work out how on earth Marnus Labuschagne had just caught him at second slip, diving low to his left to cling on to the kind of chance a fielder would be happy to hold one time in 10.

Then again, it might also have been the moment Pope's Test career flashed before his eyes. Dismissed for just 17 as England embarked on a mountainous chase of a world-record 435 to keep the Ashes alive, he knew he had stumbled in the foothills.

We have been here before, of course, this strange territory where every Pope failure seems to entrench his place at No 3, to encourage the management to double down on his value.

But his latest misadventure took his tally for the series to 125 runs at 20. And with the exception of his first 30-odd runs on the long-ago opening day at Perth, the experience of watching him has not been relaxing.

Pope is now 64 Tests into his career, yet if anything his jumpiness outside off stump, his tendency to stab at the ball like a teenager prodding dinner with a fork, has got worse.

Even before Pat Cummins found his outside edge soon after lunch on the fourth day of this third Test, he might have been dismissed a handful of times as he yielded time and again to his need to feel bat on ball. His innings was both terribly predictable and predictably terrible.

It is hard to see how England persevere with Pope now, not when Jacob Bethell is waiting in the wings. Melbourne and Sydney are still to come, and for a 21-year-old with confidence to burn and the game to match, those two Tests could provide priceless experience before his return to Australia in four years' time.

Just as pertinently, he could hardly do any worse than the man he would be replacing. Pope now owns an Ashes batting average of 17, having failed to score a half-century in his 16 innings against Australia. This is no longer a small sample size: it is reality.

England should have taken the plunge a year ago, when Bethell averaged 52 from No 3 in New Zealand, instantly oozing the kind of composure that Pope so obviously lacks. Instead, they messed it up.

The story of how the ECB's timid agreement with the BCCI to keep English players at the IPL has been well told: while Bethell stayed in India, despite barely getting off the bench for Royal Challengers Bengaluru, Pope got another chance in the one-off Test against Zimbabwe, and cashed in with 171. When he made a century in the first Test against India at Headingley, he was deemed immovable.

Even so, there was considerable debate about whether Pope or Bethell should start the Ashes in the crucial position of first drop, and it may be that Ben Stokes and Brendon McCullum, usually two peas in a pod, do not see things the same way.

After the New Zealand series, McCullum had suggested that Pope v Bethell was a 'good problem to have', which was not the ringing endorsement he usually lavishes on incumbents.

Stokes, by contrast, has continually backed Pope, whose willingness to fill any role has endeared him to the captain. First, he went in at No 3, despite never having batted so high for Surrey. Then he kept wicket in Pakistan, and again in New Zealand when Jamie Smith took paternity leave. And until he was replaced recently by Harry Brook, he was England's vice-captain, taking charge in five Tests while Stokes was unavailable.

But Stokes's loyalty has ended up hampering his own chances of being an Ashes-winning captain. Not helped by walking to the crease before the end of the second over in four of England's six innings here, Pope has repeatedly failed to calm nerves.

After stumps on day four, it was left to Zak Crawley, who has responded well to his pair in Perth, taking his series haul to 214 with a composed knock of 85, to launch the dressing-room's latest defence of the indefensible.

'That's just cricket, to be honest,' he said of Pope's struggles. 'I've had lots of tough times, and so has everyone who's ever played cricket.

'I feel like Popey gets a hard time sometimes, and I'm trying to work out why. He's got big hundreds when we need him to against tough opposition. He's had a couple of quiet games, but I think he's an unbelievably good player who plays in a really hard role at No 3 and I think he's playing well.

'Obviously he'd have wanted more from himself than what he's got, but don't underestimate some of the good knocks he's played.'

Unfortunately for Pope, those knocks are now fading in the memory: an unbeaten 135 in South Africa in 2019-20 that seemed to confirm him as England's next great batsman; 145 against New Zealand at Trent Bridge at the start of the Bazball era; an impish 196 against India's spinners at Hyderabad.

The calculation all along has been that Pope will, at some stage, pull some rabbit from the hat and win a game by himself. But the wait has gone on too long, leaving Joe Root too regularly to walk out and face the new ball – a state of affairs exacerbated by the struggles of Ben Duckett.

Remove Ireland and Zimbabwe from Pope's record and his averages drops from over 34 to under 32, which is no basis on which to launch an Ashes campaign.

Stokes can't on the one hand demand toughness, while presiding over a selection policy that feels increasingly weak. It may be too late to win back the urn, but it's not too late to put Pope out of his misery.