Commencing with the role Virat Kohli played in changing the Indian coach, it has been fascinating to watch the influence of current international captains on their respective teams.

Kohli didn't have the same harmonious relationship with Anil Kumble that he enjoyed with Ravi Shastri when he was cricket director. The fact that India have now reverted to Shastri as coach prompts the question: "Why change something that isn't broken?"

If a coach is to be inflicted on a captain then at least it should be someone with whom he's comfortable.

On the subject of captains and selection, I'm not in favour of the skipper being on the panel. I used to believe the captain should have a vote, but I was dissuaded of that notion by the wise counsel of Richie Benaud. He explained that a captain might be tempted to justify his choice by utilising a player in favourable circumstances.

Joe Root is a good example of Benaud's theory of the captain having input into selection but not a vote. It was widely trumpeted that Root got the team of his choice before the first Test and this seemed like a good idea after England comfortably won the opening joust.

Nevertheless, the Australian fast bowlers would have been salivating when they saw that Root chose as his No. 3 batsman a Yorkshire team-mate and former flat-mate, Gary Ballance.

There's no doubt Ballance is a determined cricketer and a successful first-class batsman, but his flawed technique and limited range of shots isn't suited to No. 3 in an Ashes series. The ideal No. 3 should be able to take charge of an innings at some point, and Ballance is too easily tied down not only by accurate pace bowlers but also good spinners. It was a strange choice, considering he doesn't bat at three for his county.

The other dubious Root choice was spinner Liam Dawson. There's always a red flag when a spinner is chosen because he can make runs. England already has a capable one of those in Moeen Ali and he's a better bowler than Dawson. On the evidence of Lord's, it's time Moeen was recognised as England's premier spinner.

The England hierarchy, perhaps blinded by the team's success in the shorter forms of the game, has been guilty of picking too many supposed two-way players in the Test side. They have two extremely efficient allrounders in Ben Stokes and Chris Woakes (when he's fit). They need to fill the other nine spots with specialists.

After England's comprehensive first-Test victory, Root hinted that he'd like a stronger challenge from his opponents. This comment comfortably resides in the category of "be careful what you wish for"; England went from 211-run victors to 340-run losers in the space of a week. A cheeky opponent might ask: "Is that the type of challenge you were looking for, Joe?"

One big difference between the first and second Tests was the presence of Faf du Plessis at the helm of the South African side. It's no coincidence that that resulted in a much-improved performance from the team. Du Plessis is a hard-grafting cricketer but a natural captain. He impressed with his leadership in South Africa's series win in Australia, and his firm hand was again evident at Trent Bridge.

Good captaincy is hard to define but you know it when you see it. Sometimes it can be as simple as du Plessis' encouragement to Chris Morris: "Bowl as fast as you can and forget about everything else." This had the desired effect, as following that advice, Morris turned an unimpressive opening spell of three expensive overs into match-changing figures of 5 for 45.

It's notable that South Africa achieved their massive turnaround without a coach, as Russell Domingo had returned home due to the unfortunate death of his mother.

The moral of this story? Make sure you appoint the right captain, ensure a strong selection panel and only then worry about finding the appropriate coach.