Welcome to Isak-Land: CRAIG HOPE goes inside the Cold War nuclear bunker that built Newcastle's £150m weapon of mass destruction – with help from a burger restaurant, a stolen sack of footballs and 'the explosion'

We are standing on a centre spot, five miles north of Stockholm, where 16-year-old Alexander Isak once waited to kick off. His eyes, unlike mine, were not on the majestic, retro floodlights or the nearby block of flats they rival in size.

‘He had a look in his eye,’ says Peter Wennberg, technical director of AIK’s academy. He points towards the dugout of the Skytteholms ground where he was that night, opposite the only stand of 1,000 seats. He turns us 90 degrees to face the goal.

‘Alex had noticed their goalkeeper too far from his line,’ he says. Rather than explain what happened next, Wennberg plays it out. One step. One swipe of his right leg. One-nil to AIK’s Under-19s.

‘Boom! It showed his belief, intelligence, ability. His courage. We all turned to each other, “Oh my God!”.’

Welcome to Isak-land, as Wennberg said to me on arrival at the club’s academy across the road. This is where the world’s best striker was made.

Rasunda Idrottsplats, in the district of Solna, is the academy’s home. It was also a Cold War nuclear bunker. In the windowless and airless boot room, tumble dryers and all, there are boxed-up military materials which staff are not allowed to move.

‘Hey, at least we are safe here if the Russians come,’ says Wennberg.

Isak felt safe here, and you understand why. Descending the 15 steps from ground level, escaping the skin pinch of -3C and a city where every step is to a soundtrack of gravel and grit, the warmth hits you, and that has nothing to do with the rise in temperature. Wennberg and every coach embrace each young player, be it with a handshake or hug.

There are balls and cones but no bells and whistles. ’We do not hoover, clean and paint for you coming,’ says Wennberg, 49, a furnace of wit and enthusiasm. Any money from Isak’s £8million club-record sale to Dortmund in 2017, you suspect, was invested elsewhere.

But this underground base is a very grounded environment, from the communal boxes of pears and apples on the floor of the only corridor, to the wooden benches and chipped paintwork of the dressing-rooms leading from it. IKEA, this is not. One boy, lithe like Isak, sits beneath the peg that once belonged to Newcastle’s £150million-rated star. ‘No pressure,’ I tell him.

In the gym next door, a mural of a smiling Isak – depicting the moment on his 17th birthday when he scored twice for AIK’s first team against city rivals Djurgardens – watches over those who want to be just like him. There is a silhouetted mural next to Isak and its meaning is clear – it could be you. Not that it was always going to be Isak. He started training here when he was six years old. For the next decade, he was good, but not great.

Alexander Snacke was his team-mate from the first day until the last. We are sitting in the coaches’ room and the scar that divides his kneecap explains why he is here and not, like his friend, preparing for Sunday’s Carabao Cup final against Liverpool.

‘He was not our best player,’ says Snacke, now Under-14s assistant boss. ‘Then, at 16, something happened. It was like his body hit the right dimensions and all of the extra training he had done came out. It just clicked, like a switch, an explosion. I have never seen that happen to anyone, as a player or coach. It is usually gradual. He went through the roof. At 15, I remember Peter and the other coaches speaking to him. He needed to step it up. He listened and kept going. Then, we realised. I was a centre-back, so I knew before most.’

In training?

‘Yes.’

Oh, how was that?

‘Horrible! Terrible! For 30 minutes he could do very little. Then, for two minutes, he was like, “OK, now it’s fun to toy with you”.’

Snacke tilts his arm at a 45-degree angle to demonstrate Isak’s rise.

‘We played an Under-17 national semi-final, the biggest game of our lives. We won 3-0 and he assisted all the goals. We were a year younger, but he was by far the best player on the pitch. That was when we knew, “OK, he’s too good for us now”. He played a few games for the Under-19s and then into the first team, aged 16.’

Everyone here has memories of the club’s youngest top-flight scorer, and memory of him is never far away. In a second coaches’ room, more akin to war room with its laptops, diagrams and tactics boards, there are two pictures of Isak on the stone walls of this subterranean vault.

‘There he is, watching over, checking on me,’ says Filippo Biliotti, who coached the age group below. ‘When I see him on TV, I feel great pride for AIK. But what he is doing, we saw it first.’

Wennberg adds: ‘It is true. The fakes and feints, he did them with us. We watch him do something amazing and text each other, “Hey, remember when he did that here?”.’

I mention Isak’s stupendous assist against Everton two years ago, when he beat five players, some of them twice.

‘He always had this,’ says Wennberg, mimicking the movement. ‘The drag of the ball. Bop, bop. We call it the lateral movement of the leg. The space in which you can control the ball – like a boxer’s reach. Isak’s is extraordinary. We played him central midfield, too, to get a 360-degree view of the game. You combine his technique with vision, you have something special.’

We are outside now, crossing the pot-holed car park, and watching the Under-17s train.

‘Alex’s moves have changed my talent identification,’ says Wennberg. ‘I am now looking for what he has, the complexity of doing many things at once. This is the DNA of AIK. We work with ballers, street players, how they get their body between the opponent and the ball. Alex had that.’

A ball flies towards us and I duck to avoid it. Too high to control, I offer in defence of my cowardice. ‘Maybe we need to work more on their shooting,’ smiles Wennberg.

With that, we crunch the few hundred metres to Skytteholms, the academy’s second site where Isak scored that goal from kick-off. He made this walk thousands of times. Waiting at traffic lights for buses, trams and Volvos to screech by – only the British attempt to cross on the red man – I observe how ingrained in real life this is for the players. This is no gated complex in the countryside. Rather, Wennberg tells me, pointing to the high-rises, it is Sweden’s most populated community. We cross Solna’s main road and arrive at Max Burger, next door to Skytteholms.

‘It’s not ideal, is it?’ says Wennberg. ‘Alex spent a lot of time in there! The good news is, it’s going. That will be a happy day.’

Snacke makes me laugh when he later says: ‘Max Burger is easily the restaurant I’ve eaten at most in my life. We used to go there and then come back to train.’

He shows me a picture of him and Isak inside, pulling faces. This was their common room. If the coaches could not find the players, they’d go to Max. But for all of the burgers, there was never any meat on Isak. Wennberg has two stories that explain why.

‘Lots of balls were going missing,’ he begins. ‘Where are the f***ing balls? We were looking everywhere. Then one night I was working late and left to walk home. By the pitch I saw Isak, Snacke and a few others. They had their own sack full of balls, stolen balls! They took one every evening until they had enough to do their own sessions! You could not be mad with them.

‘There was another time, Christmas Day. There was snow on the pitch but Alex and a couple of them wanted to play, so we did. It was always about football with him.’

Wennberg is joined by Johnny Gustafsson. He was Isak’s coach at Under 16 and 17 and his school mentor. Back at Rasunda, we retire to what are the only two sofas in the entire bunker.

‘You have heard about the change, yes?’ says Gustafsson. ‘OK, so it was around this time when he was getting close to the first team that we had an important game for the Under-17s. It was six hours by bus. I asked if he could come, just in case we needed him. “Yes, of course,” he said.

‘We were 3-0 up very early, so we didn’t need Alex. He was sitting beside me, “Please, put me on. Please. Please!”. I’m like, “F***, if he gets injured, I’m in trouble”. I put him on. He took the ball and it was like a video game. He looked at me and smiled. It was at that moment he could do whatever he wanted. It was not fair anymore. That was his last time with the boys. That was goodbye to under-age football.’

There is one more tale of that period, and the vault is filled with laughter as we relive it. Jesper Bjork worked with Isak before ‘the change’.

‘I struggled with him,’ he says. ‘He would be outstanding in the big games, difficult to motivate in the others. We had to work so hard with him. I then left to coach another youth team before returning here. During that time, we played AIK. Alex destroyed us in 10 seconds, 1-0. Game over.’

‘Are you sure that wasn’t your tactics?’ offers another voice.

‘My tactics did not matter!’ says Bjork. ‘Alex was a codebreaker!’

The 502 bus runs between Solna Centrum and Bagartorp, the settlement where Isak lived. He made this three-mile journey every day, passing what is now the Strawberry Arena, home of AIK and the Swedish national team. The dream was in his head, as well as outside the window.

I disembark at Bagartorp and quicken my step through the underpass. This is literally the other side of the tracks, isolated from Solna by a monstrous train repair depot. This was Isak’s world. A circular estate of multi-coloured, small-windowed flats. The balconies should not be mistaken for affluence.

Here he lived with his father, a teacher, and his mother, a carer. They had fled civil war in Eritrea in the 1980s. Everyone I speak to says the same – Isak could not have wanted for a more supportive family, including his older brother and sister. But he also had to stand on his own two legs, as skinny as they were. For on these scraps of worn and dusty grass separating the flats, he played football against older boys from the age of five. He needed to have his wits about him, and not just because of the shadowy underpass.

Climbing the hill out of Bagartorp, I refuel and reheat inside a cafe beneath a more stylish residential block. There are plants, clean curtains and wicker furniture on these balconies. When Isak returns, this is where he comes. His parents live here now.

‘His father comes in,’ says the cafe’s owner. ‘He is a very nice man.’

Like father, like son, it would seem.

Later, I ask Wennberg to tell me about Isak the boy, Isak the man. They are still in contact, mostly via WhatsApp.

‘I like him,’ he says, and those three words feel as powerful as three hundred. ‘He has been in my arms. He has told me happy stories, sad stories, funny stories. If he gets injured and that’s the end, I will be there. I know he has not forgotten.’

Snacke tells me that Isak’s celebration, when he points his thumb over his shoulder, is a nod to his upbringing, to those who were there from the start.

‘He was, he is, super intelligent,’ says Wennberg. ‘He would have gone to university. He was always in the top three players for academic results. If not a footballer, he would be high in the company sphere. An executive. Or a psychologist. He is a thinker. He read the ancient philosophy of Stoicism. He sees social patterns. Often, in the dressing-room, the only people laughing with him were the coaches. He was laughing and winking at us. That was his level.’

Sometimes, it was more base-level humour.

‘We were on a team walk abroad,’ says Snacke. ‘Alex was going around, from behind, grabbing us by the leg and barking like a biting dog!’

Isak walks his own dog on Tyneside’s streets now, much to the amusement of fans. He also still appears online to play FC25 with his old mates.

‘It’s a bit surreal when he pops up,’ says Snacke. ‘He plays Monopoly on the PlayStation too, but some of us can’t get in because the stakes are too high!’

Not that Isak is flashy. After signing for Dortmund, he returned to Rasunda in a green Audi.

‘He parked on the side of the pitch,’ recalls Wennberg. ‘It was not arrogant, he is humble. He was a teenager, it was just where he parked!’

On entering the bunker, Isak did not take off his shoes, as is the rule. A kit-man shouted after him. Isak replied: ’Hey, I don’t think so, my transfer paid for this new floor!’

‘That is just his humour,’ says Snacke.

Shoes, in fact, are part of the story of the day Isak left AIK, aged 17, for Germany.

‘I remember it so well,’ says Snacke. ‘There was a lot of speculation, Real Madrid and others. Then, one day, he came and got his shoes and left, and that was it.’

Was that a happy day, or a sad day?

‘It’s a happy day,’ says Wennberg. ‘There is no magic pill. No fairytale. It is down to work ethic, courage. If we have something magic here, it is the environment. Look around, we are not all sat here in Newcastle shirts. We are working on the next Isak. Of course, we are so proud of him. He is a superstar now, but he’s still our friend. He’s still Alexander.’

As I leave, Wennberg taps the handle of the steel door, reinforced, just in case the Russians ever did come.

‘Alex has opened this door a thousand times,’ he says.

When I entered through it four hours earlier, I had hoped it would unlock the secrets to the making of Isak, and it did.

And so, from a nuclear bunker in Sweden, came Newcastle’s weapon of mass destruction. Liverpool, be warned. There will be no underground hiding place at Wembley this weekend.