It is the question that Gareth Southgate admits he has turned over and over in his mind. Who plays alongside Declan Rice in his England midfield at Euro 2024? “In the last few months I’ve been thinking: ‘Declan with who?’” the manager said two weeks ago. “And: ‘Who if without Declan?’”

Let us move on from the second part of that because it is simply unthinkable. There is no other No 6 at Southgate’s disposal, after the falls from grace of Kalvin Phillips and Jordan Henderson. And that, as an aside, overlooks how Rice’s best position may very well be as a No 8.

It is the first part of the equation that pounded with renewed intensity after England’s 3-0 friendly win against Bosnia and Herzegovina at St James’ Park on Monday. If the composition of the midfield is the endless conundrum, then Trent Alexander-Arnold is perhaps the biggest reason why.

Southgate knows he has a unique talent in the Liverpool player, one he is keen to harness and there was a point at the end of the 2022-23 season when he seemed to have found the clarity. Southgate had tried Alexander-Arnold once before on the right of a midfield three in a 4-3-3 system – against Andorra at Wembley in September 2021 – and it did not work.

But then, in the qualifying ties against Malta away and North Macedonia at home, it did. It was wonderful to see Alexander-Arnold strut his stuff as the right-sided No 8, showing off the full range of his passing, albeit against low‑ranked opposition. His England future looked set and it did not involve him playing at right-back.

Things have changed. The shift has been subtle but significant and it has been driven by the inexorable rise of Jude Bellingham during his debut season at Real Madrid. Southgate realised early on this season – in the friendly against Scotland at Hampden Park in September, to be precise – that he needed to have Bellingham as high up the pitch as possible, in a No 10 role, and so began the move from 4-3-3 to 4-2-3-1.

Consider Southgate’s words after the Wembley friendly against Australia in October when he started Alexander-Arnold at right‑back but asked him to get up and across into midfield. After the hour, Southgate moved him to the right of the midfield two in the 4‑2‑3-1 and he watched him come to seek space to the right, away from a congested central zone.

“I think he’s an 8,” Southgate said. “Although we didn’t play with an 8 [against Australia], which is why we got him in at full-back, it is an option. He’s got qualities that are very different to all of our midfield players and we want to keep looking at it as much as we can.”

It is an option that Southgate has not really explored and certainly not against top-level opposition; partly through the formation shift, partly through circumstance. Alexander‑Arnold was unavailable for the September fixtures and, crucially, the ones in March against Brazil and Belgium. Conor Gallagher partnered Rice in the first game; Kobbie Mainoo was alongside him in the second.

Alexander-Arnold did start both of the November qualifiers in midfield. He was on the right of a three against Malta at home, then the right of a central two against North Macedonia away, which was where he returned against Bosnia and Herzegovina.

All eyes were on Alexander-Arnold, who had Gallagher as his partner at the outset, because there is almost a yearning for him to make it work. To many fans, it is a fight between Alexander-Arnold and Mainoo for the starting spot in England’s opening group tie at Euro 2024 against Serbia on Sunday week. They play their final warm-up game against Iceland at Wembley on Friday night.

The thing for Southgate against Bosnia and Herzegovina was that Alexander-Arnold did not really affect the game from midfield against physical, five-at-the-back opponents. He looked polished on the ball as always but there was little penetration. England were clogged.

Yet when Alexander-Arnold was moved to right-back in the 62nd minute, Adam Wharton coming on alongside Gallagher for his debut – straight after Cole Palmer had scored for 1-0 from the penalty spot – it was different again. Doubtless, Bosnia and Herzegovina were demoralised by the concession and they would tire but Alexander‑Arnold played with greater liberation, pinging his passes, even getting forward to score the second goal with a lovely angled volley.

For Southgate, nothing is simple. The sample size with Alexander‑Arnold in midfield is frustratingly small and on a related point he has played only once in the same midfield as Bellingham – in the Andorra game almost three years ago. Southgate was asked how he felt about using Alexander-Arnold as a midfielder in a tournament game. In other words, alongside Rice and behind Bellingham because the latter is unlikely to play as a No 8.

“That is the unknown,” Southgate said. “Obviously with Gallagher, with Mainoo, even with Wharton you know exactly what they can and what they can’t do. None of these players can do everything so you are trying to work out what is the right balance. Declan is going to be in there so what is the balance with him?”

The answer could be that there is no single answer. Southgate said the midfield could be different in different matches, depending on the opposition, while in-game changes will be key. The options and nuances need not be a headache. “I think we will play against a back five at certain times and we have got some good options – both what we start with but also what we can adapt the team to during matches,” Southgate said.

“We were very pleased with Trent [in midfield against Bosnia and Herzegovina]. And equally what we saw in the last half an hour is also an important option for us. We are going to have different challenges in this tournament and we are going to have to have different ways of solving problems that teams pose us.

“In a game like this [against Bosnia and Herzegovina], we felt there would be more space where Trent’s quality at full-back could help us. Against a wing-back system that could be helpful and in midfield he is still learning and discovering the role, so positionally at times it is going to be different for him. At times, you saw moments of quality with his passing. So both positions are really important for us.”

Wharton was a plus point, particularly in terms of the speed of his decision-making on the ball, his desire to play forward. He has impressed everybody with his calmness and he is ahead of Curtis Jones in the battle to make the final squad cut.

There is, of course, another strand to the debate. It is the lineup the internet wants to see: Rice holding, Bellingham and Phil Foden as twin central attacking midfielders. It is what Pep Guardiola would do, except this is not necessarily true. The Manchester City manager often starts Foden on the left but grants him the licence to drift inside. It is not about where these type of players begin, rather where they end up. Southgate is massively unlikely to bend to the fantasy selection as he worries about the defensive shape out of possession. As ever, he has plenty to ponder.