Half an hour after England had been booed off the field, a pre-planned full-time message was still dancing on screens around the perimeter of Wembley Stadium. “NEXT STOP: EURO 2024!” it read. After this performance, it felt like a mild threat.

Iceland won’t be going to the tournament, despite ending Friday night’s friendly as deserved 1-0 winners through an early goal by Jon Dagur Thorsteinsson. But England will catch the Eurostar to Germany on Monday with the crowd’s jeers fresh in their memories.

When Southgate announced his bold young squad on Thursday, there were two schools of thought. The first said that finally he had listened to form over favouritism, that England would go to the Euros with a band of fearless international rookies eager to show their talent. On Friday night, England set about illustrating the second school of thought: that Southgate has gambled on a lot of unproven potential.

In reality there was enough experience on the pitch to beat Iceland. Yet this was a performance of strangers confused by each other’s runs, of passes going astray, of gaping holes billowing open in England’s midfield. The 80,000 watching on let their feelings be known, and you were left to wonder whether the week before a major tournament was really the best moment to attempt squad reincarnation on an industrial scale.

Southgate has carved off nearly half of the players that were at the World Cup 18 months ago, losing nearly 400 caps of experience. There are 12 tournament debutants in the current squad compared to only three in Qatar, and the median number of caps has dropped from 23 to 12. It is a gamble, and while blame for this defeat shouldn’t lie at the door of rookies like Anthony Gordon, Kobbie Mainoo and Marc Guehi, the team had something of a lightweight feel, a sense of boys in men’s shirts.

“I completely understand,” Gareth Southgate said of the boos. “We didn’t play well enough to keep them excited. Had we scored, that might also have masked some flaws tonight. From my perspective, I’ve learnt a lot from the game. To have the fans with you obviously makes a massive difference, but you have to do enough to keep them with you.”

There are some caveats to cling to. Better players will return to improve the team. Jude Bellingham is still on holiday. Bukaya Saka was only fit enough for a late cameo. Jordan Pickford was given a rest, and won’t be too worried about his place after Aaron Ramsdale allowed a first-half strike to skid inside his near post.

None of this will necessarily have great meaning when the tournament rolls around. England will still arrive as one of the favourites. They still have a winnable group containing Denmark, Serbia and Slovenia, and the reality is that it’s quite hard to get knocked out of the group stage these days, when third place is still likely to be rewarded with a spot in the last 16.

But confidence will be knocked, and faith in the plan will be questioned. A front four of Gordon, Palmer, Phil Foden and Harry Kane couldn’t score against Iceland at home. And beyond Saka, there didn’t feel like many top-level game-changers waiting on the bench to make a difference.

Right from the start, it felt like a flat night. The Mexican waves began after five minutes, Iceland scored after 12, and by 20 minutes the crowd were cheering paper aeroplanes according to how close to the field they landed. England’s players were arguing with each other all over the pitch. Kane demonstrated exactly where he thought Palmer should have been standing to prevent Iceland’s goal, and Walker had it out with Rice.

Gordon was a bright spot as his pace caused problems behind Iceland’s right-back Bjarki Steinn Bjarksason, but his lack of end product became a theme, with crosses and shots sent wildly off target. Palmer was more productive and he should have chalked up an assist when Kane butchered a first-time finish over the bar from close range.

But there were also causes for concern. The world’s 72nd ranked nation carved open England’s back line with alarming regularity. Kieran Trippier’s role as makeshift left-back offered little in the way of overlapping threat and when he did try to control the ball with his left foot in the first half, it bounced through his boot like it was made of papier-mache. He was later replaced by Joe Gomez, another misfit left-back.

There were loud cheers for Trent Alexander-Arnold and Saka when they came on in the second half, and the duo added some much needed energy down England’s right side, but they could not spark a late comeback.

Southgate was relatively satisfied with the chances created, despite England taking only one shot on target, to Iceland’s four. He was more concerned by the team’s haphazard defensive shape. “Out of possession we didn’t do well, we were too stretched. That’s something we’ve done well in the past few games but it was off tonight.”

The manager used the phrase “physical issues” several times in his post-match press conference and seemed genuinely troubled by the state of the team. There are players recovering from injury in Guehi, Saka and Kane; a fresh injury to John Stones who was troubled by his ankle and brought off at half-time; players sidelined like Dunk and Shaw; and then Bellingham, still to return on the back of a brutally intense season for a 20-year-old.

England have plenty to fix, and perhaps this defeat will at least serve to gather thoughts and sharpen minds. Things can only get better when they meet Serbia in their Group C opener next Saturday. Next stop: Euro 2024!