Jude Bellingham is being dubbed ‘the world’s oldest 19-year-old’ in Dortmund

Sitting alone in the away dugout of Werder Bremen’s Weserstadion, his breath clouding the air like steam driven from only the most powerful of locomotives, Jude Bellingham waits patiently to speak to the TV cameras. It is little wonder they have asked for the Borussia Dortmund midfielder, the star of a 2-0 victory here in north-west Germany.

He fiddles briefly with some strapping around the left knee which is said to be troubling him. Not that you would know. At his feet are half-drunk bottles of water, torn energy sachets and scraps of paper, once the preserve of tactical instruction.

But amid the matchday debris, redundant and worthless now, rests the planet’s most valuable young footballer. Blindsiding the fluorescent coats, I approach him, only to feel the agitated palm of a club official, typically protective. Bellingham is 19, he needs shielding from the outside world. Except, he doesn’t.

‘Well played, I’ve come from England to see you,’ I offer.

‘Thank you,’ he says, relaxing into broad Brummie and leaning over to bump fists. The connection disarms the suit.

‘Should have scored, though, shouldn’t I? I had three of them. Their goalkeeper turned into Manuel Neuer!’

Here, he is just a teenager talking football, mourning lost goals in much the same way as the Sunday morning plodder in the pub. After scoring twice in a 5-0 win against Stuttgart in October, Bellingham could not sleep because of a missed chance for his hat-trick, waking up next to the phone on which he had watched said moment over and over.

We share a few words about this evening’s Champions League tie with Chelsea and, before the nod for TV, I wish him luck for the game. Not that he needs it.

Bellingham is in control, on and off the pitch. As his manager, Edin Terzic, later tells me: ’Jude is the oldest 19-year-old player in the world.’

Outside the dressing-rooms, it is communicated that Bellingham will not be speaking to the press. I am grateful now for those 30 seconds in the dugout. He has not, local reporters say, been allowed to do anything other than interviews with in-house channels and rights-holders since the World Cup. Speculation over his future has seen to that.

There are others, though. I notice Julian Brandt, who had a reputation like Bellingham at a similar age. The winger is 26 now and, despite a fine goal here, has never fulfilled that promise. He is speaking in German nearby and seems expressive and engaging.

Any chance of a few words in English?

‘Absolutely,’ he grins.

So, what is it like playing with Bellingham?

’S***!’ he laughs, his mischief confirming my instinct. ‘No, he’s an incredible talent. I love his way, how he plays football.

‘He is sometimes over the top, yelling at the ref or some team-mates, but this is him. He is a really good guy and we have a lot of fun with him. If you want to have dinner with him, it’s no problem. You speak with him, and he’ll come. If you want to have a beer with him, it’s no problem either.

‘With all the pressure he gets, all the publicity, he’s just a boy. For me, that makes him special, it’s astonishing how he deals with it.’

What can he achieve in his career?

‘Everything,’ says Brandt, a German international. ‘That’s the point, if he stays healthy and has the right mind and stays calm, there are no limits. He can do everything.’

But his comments about ‘yelling’ resonate. Bellingham was frustrated with his team-mates here, especially right back Julian Ryerson, a January signing and six years the Englishman’s senior.

At first, it feels like petulance, toddler arms and eyes to the sky when Ryerson is slow with a throw-in and later a pass. Bellingham, I note, is getting too big for his boots.

I am wrong. His boots fit just fine. Rather, he has outgrown this league and this team, just two-and-a-half years after joining from Birmingham City.

He starts in a deep midfield role in front of centre-backs Niklas Sule and Nico Schlotterbeck, a stout pair more akin to nightclub doormen. Bellingham, though, is the adolescent who needs not ID to prove his maturity. He is already a man in these surrounds.

There is a look of Steven Gerrard as he strokes a ball wide and bursts between defenders, elbows clearing his passage, to meet the return cross. He connects on the volley, left-footed, only for goalkeeper Jiri Pavlenka to flip over the crossbar. A Danish colleague sitting next to me lets out the involuntarily, and internationally recognised, ‘What a save!’. Neuer, you see.

The same Dane is ‘ooh-ing and ah-ing’ when Bellingham does that Lionel Messi thing – run, stop, start, see you later – and declares, ’He is just superior’.

By now, Bellingham is playing as a shadow striker. You realise, over 90 minutes, this is perhaps the best use of him. Early control, late flourish. Dominate first, decorate later.

Dortmund’s opener is scored by Jamie Bynoe-Gittens on 67 minutes. Yes, another English teenager.

‘Watch out for him, he is the next one,’ says Yannick Hueber of Sport Bild. ‘He told me in an interview recently he wants to win the Ballon d’Or. He is so fast, so direct’.

Indeed, it is the 18-year-old’s pace that gets him in position to lash home with only his second touch after coming on. Bellingham is the first to congratulate him, but maybe that is because he’s simply quicker than the others.

‘Jude has been so good for me,’ Bynoe-Gittens tells Sportsmail afterwards. ‘He talks to me daily to see how I am. It’s a big inspiration. He’s 19, and he’s doing what I want to be doing. He’s a big idol for me.’

Everyone idolises Bellingham here. As he boards the team bus, rice bowl in hand, an excited gaggle of Bremen staff request, and are granted, selfies. For them, it will probably be the last chance they get.

‘There is no way he stays at Dortmund next season,’ says journalist Hueber as we chat before the game. ‘It’s still open what club he will join. But his development has been too quick for the other players. He must make this next step.’

Liverpool are the favourites, but their project looks broken. Bellingham played alongside former Reds midfielder Emre Can on Saturday, and they are both better than anything at Anfield right now. Hueber also suspects they cannot pay the £150million which Dortmund will demand.

He, and others, say Real Madrid could emerge as the most likely destination. Bellingham and his family – dad, Mark, has a key influence – have ruled out Chelsea and Paris Saint-Germain because of misgivings over off-field strategies. Both Manchester clubs have an interest and sources in Germany say Newcastle have asked questions.

‘Dortmund would prefer to extend his contract (it expires in 2025) but they know this is not possible,’ says Hueber. ‘The truth is also that they will need the money from Jude to build a team for next year.’

Later, I put it to head coach Terzic that this will be his last season working with Bellingham. The 40-year-old is amiable and happy to converse in English, but to this enquiry he bristles.

‘He is our player,’ he states. ‘I know there are many rumours. This is never something me and him are talking about. We are only talking about improving and pushing him to find his limit. The rest is something that you guys talk about.’

Back on less thorny ground, what is his limit?

‘The one thing about Jude is that we don’t know,’ says Terzic. ‘He was outstanding today, again. He is one of our leaders. You could see in the second half, he controlled the game. You can see he is taking more and more responsibility.’

When Bellingham does leave, there will be no animosity among supporters. On the tree-lined Alfred Ries Platz an hour before kick-off, where fans of Bremen and Dortmund mix freely and drink beer with even greater abandon, there are several wearing brilliant yellow ‘Bellingham 22’ jerseys.

‘He is our best player,’ says Patrick Bode, 28, a teacher. ‘Once he’s on fire, the whole team is on fire. But we expect him to go. He’s too good. He only cost £17m. But after 10 matches we all said, “Wow, he can make a difference for us”.’

Do they accept the Dortmund model – buy, develop, sell?

‘Ah, the farmer’s team… we don’t have another choice,’ says Bode. ‘We don’t have the money. You can’t compare the Premier League and Bundesliga economically. For Dortmund, it’s the only way to go. As fans, we have to be honest.’

As a British ex-pat in the charming Mit Schmackes pub on the otherwise charmless Hohe Strasse in central Dortmund says: ‘This place is just one big grey block’. There is, you feel, little to keep Bellingham here besides the football.

He lives out of town in an apartment with his mother, Denise, near the more scenic Lake Phoenix. The only thing illuminating the city, a mass of post-war concrete, is the football club itself.

I leave behind the pub, owned by former Dortmund defender Kevin Grosskreutz and decorated in the yellow and black of BVB, and walk 20 minutes south through the shadows of monochrome high-rises, each reaching out as if desperate to touch the blue of the sky above.

Finally, beyond a clearing of long-overdue greenery, Signal Iduna Park causes the eyes to widen. Here, there is colour, vibrancy and, on matchdays, noise.

Hey Jude, I’m told, is top of the playlist. It costs just €15 to gain access on this sleepy Sunday and I make straight for the home dressing-room.

Sitting in Bellingham’s spot, marked by his smiling picture and with Bynoe-Gittens to one side and Sebastien Haller to the other, you are struck by the cramped nature of it all. Eight showers, three toilet cubicles and one wooden bench, all within the confines of little more than a six-yard box. As unique and alluring as this stadium is, Bellingham is too big for this environment now.

But first, he must cut Chelsea down to size. There is still a chance, of course, that he leaves here with the greatest prize of all.