MANCHESTER -- Nicky Butt has a unique way of explaining the role of Manchester United's academy when it comes to turning a young footballer into, hopefully, one of the best in the world.

"I'd describe it as, when you meet the person you're going to spend the rest of your life with, the first thing you are attracted to is looks," Butt, who spent 13 years at United (387 appearances) and is now the head of first-team development for the club, tells ESPN. "Then you begin to learn about the person, you fall in love and then you get married. When you see a young player, the first thing you see is talent. But that can't be all there is, just like in a relationship. You see the talent straight away but the biggest thing then is the character."

"Thousands of players have come through this club that had more talent in their little finger than I ever had, but I got to where I did because of something else. It can't just be talent -- there has to be a lot more."

United's academy will celebrate a significant milestone on Sunday. When Everton visit Old Trafford this weekend, United will mark their 4,000th consecutive game with a youth team graduate in the squad. It's a run that stretches back more 80 years to Oct. 30, 1937, when Tom Manley and Jackie Wassall played in a 1-0 defeat to Fulham. To put that into context, Everton have the next best record in the top flight with a run of more than 1000 games over 20 years which ended in August.

This unbroken run is something United are so proud of that it formed part of Ed Woodward's call with investors in November. His mission statement is "win trophies, play attacking football and give youth a chance." The last part is one of the reasons Ole Gunnar Solskjaer was chosen as manager when Jose Mourinho was sacked nearly a year ago, but from a broader point of view, players produced by the club form a key part of its history.

In 1968, United became the first English club to win the European Cup with a team that included eight youth players, just 10 years after the Munich Air Disaster killed eight members of Sir Matt Busby's "Busby Babes," seven of which had come through the youth system. The production line was reborn under Sir Alex Ferguson in the 1990s and when United won the Champions League in 1999, the team that beat Bayern Munich in the final included four graduates from the academy class of '92: David Beckham, Butt, Ryan Giggs and Gary Neville. There would have been another in the XI had Paul Scholes not been suspended.

Nicky Butt oversees Manchester United's first-team development. Getty Images

The latest batch to make the step up to the first team picture include Marcus Rashford, Jesse Lingard, Scott McTominay, Mason Greenwood and Brandon Williams. Each is following in the footsteps of others who have made the same journey like Duncan Edwards, George Best, Mark Hughes, Giggs and Beckham, and this commitment is reflected in the club's record books. Man United's top five all-time appearance makers -- Giggs, Sir Bobby Charlton, Scholes, Bill Foulkes and Neville -- are all academy graduates. This season, 31 out of United's 34 goals have been scored or assisted by a former youth team player.

The academy in action

United can register players at the Under-9 level in accordance with Premier League rules. At 16, a select group sign scholarships and go on to train at Carrington every day. The club have a link with Ashton-on-Mersey School in Sale, about five miles from Old Trafford, to ensure young players get a real education as well as a footballing one and between the ages of 16 and 18, the players spend at least one day a week at school. On other days, teachers hold lessons at Carrington. The Monday morning after Rashford scored his first two Premier League goals against Arsenal in February 2016, he could be found playing pool in the sixth form common room.

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Their education isn't all about football and the club have had an astronaut and a Holocaust survivor in to talk to the young players. Former first-team stars are also regular visitors to talk about their own experiences -- Roy Keane has been in this season -- and there are reminders of success everywhere in the dedicated academy building at Carrington. The corridors are covered with murals of Rashford, Lingard, Giggs and Scholes while upstairs, there are shirts on the wall with names and numbers of Edwards, Hughes and Beckham. On the noticeboards in some of the dressing rooms there are words of advice written by Gary Neville. No. 3 is: "Always remember why you began to play football. You loved it for its own sake and not as a means to get money, fame, girls or cars."

United's aim is to help youngsters fulfill their potential, whether that's as a first team player at United, at another club or in another industry. They have the resources to buy almost any player they choose, and producing one from scratch to meet their exacting standards is a huge task.

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"It's hard, really hard," says Nick Cox, who took over as head of the academy in the summer. "It's up there with winning an Olympic gold medal or landing on the moon. We have to be realistic with our kids. We want them all to dream. We want them all to have aspirations, but only a handful of players get the privilege of crossing the white line at Old Trafford as a homegrown player."

"What keeps you here is character and commitment"

Butt admits it doesn't always go to plan even with the most talented boys who walk through the door.

"For me, the biggest disappointment at this club was Adnan Januzaj," says the former England midfielder. "I don't think I've seen a player, probably since Ryan [Giggs], who was as good as that. He was unbelievable. In my eyes he should have gone on to be a world superstar. He's still playing professional football [at Real Sociedad in Spain] and he will have a good career. I'm sure he's a millionaire and he won't be going to bed worrying about what bills he's got to pay, but he should have been a superstar.

Adnan Januzaj was one of the brightest prospects produced in the United academy in recent memory. Stu Forster/Getty Images

"Talent gets you through the gate here but what will keep you here is character and commitment."

Butt points to two of the most recent graduates, McTominay and Williams, as examples for other hopefuls to follow.

"With Scott and Brandon, that's just character," he adds. "Character with talent and not talent with character. It's a never-say-die attitude, a will to win. They are both talented footballers, but to get to where they have got is down to their attitude."

Scott McTominay has been one the finds of the last few years. Simon Stacpoole/Offside/Offside via Getty Images

It's not just players that are produced by the academy, either. Kieran McKenna was U18s coach before he was added to the first team coaching staff by Jose Mourinho and then kept on by Solskjaer. Neil Wood, a former United reserve team captain, is lead coach at U23 level. Neil Ryan, son of Jimmy Ryan, a former Busby Babe and assistant to Ferguson, has risen from coach of the U11s to U18 lead coach.

"It's special for me for my father to have been so heavily involved," says Ryan Jr. "That's quite a special thing to have grown up with and to be educated on. I was lucky enough to meet Sir Matt Busby many years ago as a young kid. It's in your blood. It helps me with my job. It also helps me when I'm speaking to the players and the families that we speak to, as well about the special history of this club. One of the first groups I had was Jesse Lingard's group. It's part of my job to educate the players on the history of the Busby Babes. We've had a lot of success with young players who we have been able to pass onto the first team.

"You work your way through the age groups getting valuable experience. Not just on the pitch, but off it too. Just moments when you sit round a table with Sir Alex Ferguson and talk -- those are priceless moments that you don't forget."

United make no secret of their desire to sign the best players in the world, but their goal is to supplement the imports with their own players and, hopefully, create a few superstars of their own.

"It's a tradition we're very proud of and it's in our DNA to give young players a chance," says Solskjaer. "I like to give young players a chance, they can only surprise and impress you when you give them a chance. It will definitely be more than 4,000 games. We have a great academy and it's something we're proud of."