Mourinho said he had joked with the player in training about whether a less-talented brother was masquerading as Alli, such was his dip in form.

But his revival has helped Spurs to a 100 per cent start from three games under the Portuguese coach, and given Southgate a pleasant selection dilemma.

"Jose has played him as a number 10 and that's his best position, having the freedom to run on into the box. That has been very clear for a long time," Southgate said.

"So it's great he's back on the scoring trail."

England were drawn to face their World Cup semi-final conquerors Croatia and the Czech Republic in Group D of the Euro 2020 finals. They will learn in March who their other group opponent will be – one of Israel, Norway, Scotland or Serbia. All three group games will be played at Wembley.

Southgate believes the arrival of Mourinho at Spurs will not only keep Alli on his toes but also the rest of Tottenham's English contingent – Harry Kane, Harry Winks, Danny Rose and Eric Dier.

"At the moment they are fighting to get into Tottenham's team and pleasing their manager there, so if the consequence of that is that they are in form for us then for sure (getting in the Euro 2020 squad) will be in the players' minds, but at this stage of the season they are thinking about their clubs."

Another player hoping to come in from the cold in time for the Euros – which would start and end at Wembley for England should they get at least to the semi-finals – is Kyle Walker.

The Manchester City right-back has not featured for England since the Nations League finals in June, with Liverpool's Trent Alexander-Arnold and Atletico Madrid man Kieran Trippier preferred by Southgate.

History suggests that when a player falls out of favour with Southgate – such as goalkeeper Joe Hart – it can spell the end of their international career, but the Three Lions boss says it would be "foolish" to discount Walker from his plans.

"I think, when you look at some of the positions, Joe was a really difficult call because he'd been such an important part of England's more recent history and has been an outstanding goalkeeper," he said.

"He was having a difficult time at West Ham and Nick Pope had played so well that I just felt that Nick had earned the right to go to the World Cup.

"With Kyle, we've obviously got Trippier, he's been playing very well. Trent is obviously playing well but Kyle is right in that mix.

"(Chelsea youngster) Reece James is also coming through and is another one that is pushing in that area of the pitch. So we have competition, but it would be foolish to rule Kyle out."