The weathered sign by Jadon Sancho's old family flat on the Guinness Trust Buildings estate on Kennington Park Road is unequivocal. 'No Ball Games,' it orders in big white lettering on a green background. But then boys will be boys.

Two are circumventing those rules on the morning of Mail Sport's visit by playing passies with an empty bottle of Coca Cola instead, their mums nattering nearby in the very concrete courtyard where Sancho dreamt of representing Chelsea, the club he supported in his youth.

We are here, south of the River Thames, for a wander through the childhood of the 24-year-old who considers this loan a homecoming. Not because he previously played for Chelsea. He never has. Saturday night will be his debut if thrown in against Bournemouth.

But because it brought him back to London, as close to his old SE11 postcode he has been since leaving to pursue his professional career. Born in Camberwell. Brought up in Kennington. This is home; a return to capital roots for the footballer who had 'No Ball Games' and 'Poppin' Outta Kennington' printed on his boots while playing for Borussia Dortmund in Germany.

Those who know Sancho say they want to see him with a smile on his face at Chelsea after that was lost at Manchester United. Untroubled, like when he was playing cage football at Frederick's Adventure Playground, the nutmeg king of Kennington making mugs of boys twice his age.

Frederick's is a nine-minute walk from the Guinness Trust Buildings that have stood here since 1921, not too far from The Oval cricket ground. Leaving the lads booting their bottle and the bloke checking the mouse bait boxes, we embark on that stroll. 

Beyond Kennington Underground Station. Past the Old Red Lion pub. By St Mary Newington Church. The No 133 bus passing en route. Not that Sancho ever hopped on board, routinely running to and from his estate as Norman Dawkins, his very first coach, tells Mail Sport.

'The best thing about it? I'm a Chelsea fan! So I'm happy,' Dawkins says. 'I've known Jadon since he was maybe six years old when his mum brought him. She didn't want him hanging out on the streets so he'd come with a group of boys who lived on his block. I've been doing football since 1989. It's not easy to run. You have to do it out of love.'

The greatest reward for community heroes such as Dawkins is witnessing what his fledglings go on to achieve, the added bonus being that he can now text Chelsea's newest signing in the hope of snagging a ticket or two. 

'I'm so pleased for Jadon,' he continues. 'He was only ever interested in football. Nothing else. He even inspired the other boys. He was guiding them on how to play, stopping and showing them, doing his skills and working on them.'

Away from the stringency of Premier League academies, there were no shackles placed on what you could and could not try at Frederick's. It was freestyle football. Five v five. One v one. Razzle 'em. Dazzle 'em. The tarmac was a dance floor to do with as you wish, and Sancho was not the only one who used this pocket of south London as a platform for stardom.

There was also Reiss Nelson, Sancho's close friend who is now on loan at Fulham from Arsenal. Dawkins produces an old picture. 

It shows Sancho and Nelson after their Southwark Under 11s side won the London Youth Games in 2011 by beating Richmond 2-0 in the final. Ademola Lookman, now with Atalanta in Italy, was another to emerge under Dawkins as he sums up: 'It's mad, isn't it? Who's next? I wonder who will be next.'

Unfortunately, they will no longer originate from Frederick's. Today, you will find only a building site, with signage promising a new playground coming soon. 

While that is welcomed – the old swing set was in dire need of WD40 – there are no plans to add a football pitch. Shame, really, because this concrete canvas overlooked by the forest of greying flats on the Doddington Grove estate was where Sancho learned to express his artistry in his earliest years.

That individuality was precisely why Enzo Maresca wanted Sancho, Chelsea's head coach explaining personally in a phone call how his tactical system requires wingers who can beat their full backs. 

The 44-year-old Italian promised he will get 10 opportunities a game to go one-v-one, maybe more, and Cobham sources say he has impressed Maresca enough in training over the international break that an immediate start at Bournemouth is under serious consideration.

Joe Shields, Chelsea's co-director of recruitment and talent, vouched for Sancho internally after their time working together at Manchester City's academy. His opinion carries weight at Cobham, Shields having also recommended Cole Palmer last summer.

Supporters will notice tattoos streaming out of Sancho's blue sleeves, some of which are a nod to a childhood spent flicking through comics when he wasn't performing flicks at Frederick's. There's the Simpsons family, Spiderman, Sonic the Hedgehog and more.

But his most meaningful ink, and the first he had needled on his skin, is reserved for his left forearm. It is a poem written by Sancho while he was in primary school; a touching tribute to his late sibling which he somehow recited at his funeral. 

It reads: 'You and me will stay together, you made us happy, you brought us joy, you were a special baby boy. I couldn't wait until you grew up, teach you football and win the cup. But you're gone, what can I do? Baby brother, we love you.'

Crampton Primary School is eight minutes on foot from Frederick's and our next destination, a blue banner outside boasting how it is in the 'top one per cent' in the country.

Marian Kennedy was the headteacher here. Towards the end of term, she would let the little ones join their older peers on the big playground. It was in 2005 when 'Miss Kennedy', as Sancho and his schoolmates would address her, witnessed raw talent as the boy from her reception class threw himself fearlessly into the ongoing game of football. 

The schoolyard is hidden by walls standing 7ft tall, so those strolling down Iliffe Street would struggle to sneak a peak at the future England international shouting 'megz' whenever he performed football's ultimate putdown.

When Sancho saw his penalty saved in the Euro 2020 final shootout loss to Italy alongside Marcus Rashford and Bukayo Saka, the class of Year Fives wrote him a letter. 

'You can only miss a penalty if you are brave enough to take one in the first place and we know that you will be there to take the next one,' they penned. 'We wouldn't want anyone else to represent our country and when we think of three lions, we think of you.' 

Assemblies have since been held using Sancho's story to discuss the power of pursuing your dreams, even if that takes leaving the home you love.

The Marcus Lipton Community Centre is 40 minutes away. Though there is a 2020 Porsche picking up a parking ticket upon our arrival on Minet Road, it is not an opulent area. If you want glitz, take a walk towards Westminster. 

Here you are more likely to find the grittier side to London life, emphasised by the warnings listed in the youth club's entranceway. No weapons. No hoodies. No balaclavas. Never forget, CCTV is capturing your every move.

It was here in February 2019 that children as young as three years old were present at a Thursday training session with local team Lambeth Tigers when a murder was witnessed, the fatal stabbing of 23-year-old Glendon Spence. The tragedy sent shockwaves throughout Loughborough Junction.

Sancho wanted a safe place for kids to play and that same year, he was instrumental in the installation of a new seven-a-side pitch in Myatt's Field Park, next to a Victorian summerhouse where locals have been coming together each Friday to bang drums in a circle to promote positivity. 

Sandwiched between Brixton and Camberwell, it is 10 minutes' walk away from where this community was crushed by that atrocious act of youth violence five years ago.

Originally this turf was coloured orange and black for Lambeth Tigers and had the initials 'JS' in the centre circle. Today it is back to being a green carpet, floodlights lining the cage. The locals still call it 'the Jadon Sancho pitch'. 

There is a sign advertising it as such, and three teenagers are waiting patiently for the gate's padlock to be removed so they can get to work. When one called Nathan claims he's the next superstar in waiting, his mate suggests he couldn't skin his own nan.

Sancho's story is inspiring for local lads such as this and upon joining Watford's academy, he was soon schlepping across London three nights a week for training. 

It was at 12 years old that he finally left home to join the Hertfordshire club's affiliated boarding school, the Harefield Academy in Uxbridge. He did not want to move into that Monday-Friday accommodation at the time, but listened to the advice of his father, Sean, a former security guard.

Louis Lancaster coached Sancho at Watford and tells Mail Sport how helpful it was that he inherited him straight from the cages of Kennington. 'I call them time travellers,' Lancaster says of players like Sancho. 'Everybody else's second is their minute. It wasn't only the way he moved the ball. It was how he moved his body. He had action-man hips.

'When you're in a cage, it's so small, you're constantly involved. When you go into 11-a-side, which we played at Watford, you might go two minutes without touching the ball, but Jadon learned quickly. He was so forward thinking. If everyone passed sideways, we would never get goals. The best will cut you open and that was Jadon. 

'They say now in schools that you cannot let captains pick teams because somebody will get upset. But in the cages, kids are grafting, practising their skills so they're not picked last. It can be ruthless. There are 10-year-olds facing 14-year-olds. You get slammed into the walls. You have to think fast.'

Chuckling at one memory, he continues: 'All the Watford boys were in class and I remember walking past the computer room. I look at his screen and there's Ronaldinho. All I can hear is the teacher shouting at him. "Jadon Sancho! Get off YouTube! Do your work!" He minimises it. Then as soon as she turns away, Ronaldinho is straight back up on the screen.'

Lancaster recalls asking Sancho, aged 13, what he wanted out of football. His answer was: 'I want to play for England. I want to play for one of Europe's top clubs. I want my family to be proud of me.' 

Lancaster picks up the story: 'It was the way he said it. With such confidence. Passion. We didn't want to take anything away from him. Some players like to play simple, which is fine, and some players like to be inspirational, and that's Jadon. He can produce the brilliance when it comes to the crunch. I knew he was going to be special when Watford played Arsenal.

'I know it was only Under 15s but it was so memorable. Tuesday night, under the lights, a perfect pitch, everyone watching from the balcony they had at Arsenal. It was 1-1 with 10 minutes to go when Jadon got the ball by the halfway line. He moved in and out of four players, and put the ball into the top corner. That was when I knew.

'I saw him on TV the other day, during the live coverage of Chelsea versus Crystal Palace. The camera spent 10 seconds on him in the stands. With the work I do, I look at technique and the decisions being made, but also body language. 

'Just to see him sitting there. Happy. Relaxed. Back in London. It's such a big thing, and I absolutely think he will smash it at Chelsea.

'Look at what he produced at Dortmund. He was getting goals, assists, and now he's even more mature, in an environment in which he's completely comfortable with. Whatever we've seen from him before, he can surpass that. Good luck to him.'

There were nine deal sheets – the document that provides clubs with two extra hours to finalise transfers – submitted to the Premier League prior to 11pm on deadline day. Chelsea were involved in four of them. 

They loaned Raheem Sterling to Arsenal, Trevoh Chalobah to Crystal Palace, Armando Broja to Everton, and then, last but not least, confirmed they had brought in Sancho on a season-long loan with an obligation to buy worth up to £25million. The higher they finish, the more they pay. 

Whatever happens, Chelsea persuaded United to sell at a hell of a discount. They signed him from Dortmund for £73m in 2021, the same year that Sancho last represented England as his time in Manchester became more miserable than memorable.

Chelsea hope this full circle will work in their favour, now that the boy who left the Guinness Trust Buildings estate at 12 has returned to London as a 24-year-old man. 

Sancho's journey has been a winding one, and likewise, my 10,000 steps are more than done for the day as we complete the last leg towards Brixton Underground Station, passing a chap in a Chelsea training jersey with '26' tattooed on his forehead.

Sancho will wear the No 19 for the first time in his career, taking up that vacancy ahead of the trip to Bournemouth after telling his new club he has never been too attached to any number. 

Who needs superstition when you've got sauce, as they would say in Kennington, and Sancho is certainly relishing the next chapter of his career with Chelsea after it brought him home.