Bairstow glass remains half empty

What will be Jonny Bairstow's final thought before he drifts off to sleep tonight?

Will it be the two fine innings he has produced in this Durban Test? Or will it be the drop and the missed stumping?

Bairstow has batted with more fluency than anyone in this match. Coming to the crease in both innings with his side under just a little bit of pressure, he demonstrated that he has the batting ability to succeed at this level.

While colleagues as positive as James Taylor and Ben Stokes struggled to rotate the strike, Bairstow scored at a run a ball. There were three slog-swept sixes off the spinners and three sweetly-timed boundaries off Morne Morkel. He looked comfortably good enough to make it as a specialist batsman.

Yes, he had some fortune. He survived two edges that went perilously close to leg slip (the first when he had made only a single, the second on 34) and 18 of his second-innings runs were made against the part-time bowlers Dean Elgar and Stiaan van Zyl. In other circumstances, he might have expected to face Dale Steyn and a second new ball.

But he also batted selflessly. In both innings, he lost his wicket when left with the tail and looking to plunder quick runs. He did everything that could have been asked of him. With the bat.

We probably shouldn't be surprised. Bairstow averaged nearly 100 for Yorkshire in the Championship season and, by steering his side from trouble time after time, played a huge role in the club winning the title.

He made a classy 95 against this opposition in his fourth Test and followed it with an aggressive 54 in the second innings as England chased an unlikely victory. On ODI debut, too, against India in Cardiff in 2011, he won the match for his side with an unbeaten 41 from 21 balls. The format may require different skills, but it says something about his temperament that he could thrive under pressure.

But batting is half Bairstow's job in this side. And, just as a pilot can't just be good at taking off - he needs to be able to land the plane, too - Bairstow needs to improve his keeping if he is to succeed in his current role in the side.

The stumping Bairstow missed in the second innings was tough. AB de Villiers' body would have obscured the ball from Bairstow and the turn - from around the wicket, too - was sharp. Better keepers than Bairstow have missed simpler chances. Spare a thought for Moeen Ali, though: if you beat the best with a ball that good, it must sting to go unrewarded.

But there is a pattern emerging. Bairstow also missed a stumping off Moeen - a much easier stumping - in the warm-up game in Pietermaritzburg. And he missed a stumping in his previous Test, in Sharjah, off Adil Rashid, which allowed Mohammad Hafeez to go on and score a big hundred. He also dropped him earlier on in that innings off Moeen. The damning stat remains unbroken: no England keeper has completed a stumping in a Test since 2012.

Bairstow also missed a catch off Chris Woakes in the first innings. The drop, in itself, didn't cost England. Hashim Amla was dismissed soon afterwards.

But Bairstow will remember it. The selectors will remember it. And the bowlers will certainly remember it. It was the sort of chance a Test keeper should take. His failure to do so exposed his poor footwork as much as his glovework and underlined the concern that the mistakes are not aberrations: they are the consequence of picking a wicketkeeper who is not quite good enough for this level.

The fact is, in this game, Bairstow has reprieved Hashim Amla and AB de Villiers. England may, on this occasion, get away with it. But there will be many times when such errors cost games.

England have been done this road before. Matt Prior was far from the keeper he became in his first spell in the side. His struggles keeping to the left-arm of Ryan Sidebottom eventually saw him dropped before a period working hard in the county game brought a recall. Alec Stewart, too, improved out of all recognition.

And Jos Buttler, for all his struggles with the bat in Test cricket, had become much better standing back to the seamers. His work standing up to the stumps still left a bit to be desired, but there was a reason the selectors and coaches backed him, not Bairstow, for the job in the first place: they felt he had more natural keeping talent and could, in time, develop into a fine performer.

It made sense to drop him, though. He was beginning to look frazzled and jaded. He required, like Prior, some time out of the spotlight before he came again. It is worth noting, too, that there are many other options within the England game: they do not just have to pick between Bairstow and Buttler.

They could plump for a short-term solution - perhaps Chris Read, who has developed into a fine batsman, or James Foster, who could even slip into retirement in the coming weeks or months having had little chance to show the skill that Jack Russell says has taken the art to a "new level" - while the likes of Bairstow, Buttler, Sam Billings or Ben Foakes (who is highly rated by the England camp but cannot claim the gloves at his county for now) work on their game to reach the required standard.

Bairstow will no doubt improve. He is working hard and, a few days before the Test, was said to have enjoyed his best session yet with the keeping coach, Bruce French. Nobody will regret his errors more than him. There is no questioning his hard work or good intentions.

But is the Test team the place to be learning? And has an England Test keeper in recent memory ever come into the team with so much to do to bring their game up to the standard required? And, perhaps most pertinently of all, do England need the depth of batting they have in this side to justify the compromises they are making over the quality of their keeper? Does the balance of the side, with Ben Stokes at No. 6 and men at No. 8 and No. 10 who have scored Test centuries, really necessitate taking such a risk with the keeper in order to bolster the batting?

The irritating fear is that, on the strength of this match, it might. Bairstow's batting helped them rebuild from 196 for 5 in the first innings and 197 for 5 in the second. For all the talent and entertainment offered by others in the middle-order, they have yet to achieve consistency.

So England need a wicketkeeper that can bat. Just as all international sides have also reached that inevitable conclusion. But they also need to be able to keep and, all the evidence so far suggests that, with Bairstow, too much compromise has been made towards the former. Let us not forget that the 2015 Ashes may have been decided by a keeping error: Brad Haddin dropping Joe Root on 0 in Cardiff.

Right now, Bairstow's keeping is an accident waiting to happen. England cannot feel surprised or aggrieved if his fumbles cost them this Test, this series or, one day, the Ashes. His unreliability is currently the only reliable thing about his keeping. He is, right now, a fine batsman and a poor keeper.

So, as with several members of this young side, they have a decision to make: do they continue to invest in him - as they have with Ben Stokes and Joe Root and Moeen Ali - or do they move on? There is probably no right or wrong answer, but if they decide further investment is the right decision, England supporters should expect some more frustrating days.