Gareth Southgate has defended his decision not to acclimatise his England players to the heat of Nizhny Novgorod ahead of the clash against Panama that could clinch qualification from Group G.

England - who will seal their place in the last 16 with a victory - trained at their Repino base, where it was 19 degrees, on Saturday morning before flying to Nizhny Novgorod, where it is forecast to be 31 degrees at kick-off on Sunday. Panama arrived at the venue almost 24 hours before Southgate’s squad and trained in the stadium on Saturday afternoon to get used to the hot and humid conditions.

Southgate had been given the option of preparing for England’s games somewhere hotter before the tournament, but stuck to his original choice of using Repino as his training base.

The decision is understood to have been viewed as a risk by some members of FA staff and comes a fortnight after England rugby head coach Eddie Jones was criticised for basing his side at sea level before their first two Tests against South Africa, both of which were at altitude. South Africa came from behind to win both of those Tests and their players admitted afterwards that England's struggles to acclimatise were key.

But a bullish Southgate is adamant that his decision not to head to Nizhny Novgorod early is the right one. “We never trained at the stadium before any of our qualifiers,” said Southgate. “It’s fairly typical for most of the teams when they play in the Champions League.

“When I came to the Fifa workshop they were quite keen for teams not to train at the stadia to protect the pitches. It makes sense to train earlier in the day, recover and travel. It’s about the flow of the day to leave maximum time for physical recovery.

“We kick off at 3pm, so there’s time from that session to the game. The heat is different in different parts of the country. We have to adapt to that. There’s no physiological benefit to train in the heat the couple of weeks before and thinking there’ll be an adaptation. We are a team who keep possession and in the heat that will be key when we need to attack with the ball or rest with possession.”

Despite his assistant Steve Holland apologising to the squad for appearing to leak the team, Southgate refused to confirm his starting line-up.

Dele Alli will miss out after playing on with a groin strain against Tunisia and Southgate admitted it can be hard to convince his players to be honest about their fitness during such big games.

“There are two parts to that,” said Southgate. “One is performance aspect. Is an injury going to inhibit your level of performance, which is key to the team? It’s difficult for a player. Most players are aware physiologically of their bodies and know what they can play on with.

“We’ve not lost any time with Dele, not through design but through luck and also him understanding it’s nothing more serious. We’ve been very fortunate, but also prepared well.

“It’s the first muscular issue we’ve had over the three-and-a-half weeks. To have 22 players available was unlikely. That may not happen because we’ll have contact injuries as the tournament progresses, but as a manager, you don’t take a risk with the player because a performance aspect comes into it. But players aren’t always going to tell you 100 per cent how they are. There’s a danger they may be economical with the truth.”

Midfielder Jordan Henderson added: “You know as a player when an injury is bad enough you have to come off. I’m one of the worst, wanting to battle through. But if it’s affecting performance the manager and staff will be able to see. You have to be careful and know in your own body when it’s serious enough to put your hand up and come off.”

Southgate followed Henderson by saying: “Normally Hendo plays through and I get an angry call from Jurgen (Klopp) saying, ‘Why the hell didn’t you take him off?’”

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England need a win to keep pace with Belgium at the top of Group G after they beat Tunisia 5-2, but their manager, Roberto Martinez,  said he would play a weakened side when the two meet on Thursday.

Romelu Lukaku, who scored twice, is a doubt after suffering an ankle injury but Martinez will play a second-string side in a game which is likely to decide who will top the group.

“If we could have seven days to prepare the game and then have seven days for the next game I would say carry on with the same starting 11," said Martinez.

“The reality now is that we are qualified and in a tournament like the World Cup you’re only as good as the 23 players in your squad. There’ll be opportunities for other players, there’ll be opportunities to give minutes to other players who deserve them.