How is a World Cup kit designed? Do leaks or fan backlash matter? What do players ask for?

Gomez: Mexico have knocked it out the park with new kit (1:26)

Herc Gomez can't hide his love for the new Mexico away kit and training jacket. (1:26)

Long gone are the days when football shirts were just what players wore on the pitch. In the modern era, they are everything from fashion items, to treasured memorabilia, to a sense of identity. For players, they represent high-performance clothing designed to give them a competitive edge, and for fans, wearing their team's colours can not only show support but also inspire a sense of pride.

Shirts take on even greater importance in the build-up to a World Cup. Every fan has an opinion on how their national team should look on the world stage -- when designs for England and the United States were released ahead of this month's tournament in Qatar, supporters complained they looked like training gear. Argentina's purple away shirt also proved divisive despite its message of gender equality.

What many fans do not realise is that the finished product they see is the result of several years' work from designers, marketers and brands. It is an arduous and often thankless process that involves trying to keep both fans and players happy, adapting to host country conditions and staying true to the football origins of each team.

As one former Nike brand lead who preferred to remain anonymous told ESPN: "Those kits become the nations."

How much effort goes into each design and how much do the designers care about fan feedback? When do designers start planning for the next World Cup and why are leaks not as damaging as they might seem for the biggest brands? This is a behind-the-scenes look at World Cup shirts -- from start to finish.

How to design a World Cup kit

For the biggest brands, planning for a World Cup often begins as soon as the host country is chosen.

This is the point at which they decide on their strategy for the finals -- do they want to place an emphasis on bright colours or appeal to younger fans? It is also the point at which research begins on how best to equip players for the conditions they will encounter.

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Craig Buglass was creative directing manager at Nike during the 2002 World Cup and was responsible for all the brand's shirts at the tournament -- including winners Brazil. He and his team realised the polyester-knitted jerseys usually worn by players would not be suited to the humidity of host countries South Korea and Japan. They settled on a new technology called "cool motion," which drew sweat away from the body through separate layers. All but one of its teams -- the United States -- adopted the design.

"We tried as hard as we could to convince them to take the kit but they just wouldn't," Buglass said. "We were disappointed, but it wasn't the end of the world because, with the deepest respect to the U.S., we weren't expecting them to win the event. But if you look at any of the images [from the tournament]... Every picture you'll see of the U.S., they are absolutely drenched."

The design process then begins in earnest around two years before each World Cup, as designers start putting their ideas down on paper and focus on the colours in more detail. Buglass chose the theme "massive colour" for Nike in South Korea and Japan -- making each nations' colours as loud as possible -- after being inspired by a neon orange flyer he was handed outside a nightclub in Amsterdam.

"At the time I was in the process of designing and I thought it would be great for the Dutch national team," Buglass added. "Off the back of that I thought, 'Well, what would be the versions for all the different countries I was designing for?'"

Designers can choose to be more subtle with how they use national colours. According to Rob Warner, who has worked for Umbro and Puma and who designed Italy's World Cup-winning shirt in 2006, the fact so many national teams play in similar colours forces designers to get creative.

"Everybody knows that Brazil play in yellow, but not everybody knows the significance of the canary or whatever it might be," Warner said. "We put a baobab tree on the front of the Senegal shirt in 2006 and when we presented it to the federation, the assistant coach... actually started to cry because he was so proud that this tree was on the front of this shirt."

Designs are agreed upon internally, a process which lasts around three months, before federations have their say. Buglass designed Nike's shirts for the 2002 World Cup without a collar, but South Korea's football officials convinced him to make an exception for them as they believed not having one would bring bad luck. He soon found himself fielding multiple calls from local journalists when the hosts went on a remarkable run to the semifinals.

Sometimes requests from federations can be more delicate. "Probably the most back-and-forth I can remember was actually 2006, designing for the Ivory Coast," Warner said. "Their national icon on the front of the shirt was an elephant, and so to them the length of the trunk on the elephant was of significance to men in the Ivory Coast."

The input from players varies. Portugal great Luis Figo was rarely interested in the design of the shirt, according to Buglass, but would instead ask about the fit of the socks to the point of obsession. Other players require a more tailored approach -- striker Peter Crouch needed specially adapted shorts and socks for his 6-foot-7 frame when Warner was working for Umbro. The brand also had to apply for special permission from FIFA to use smaller lettering for Shaun Wright-Phillips' surname.

FIFA rules can limit designers' creativity, although there are ways of testing the limits.

Warner, who founded the Spark Design Academy with Buglass, joined Puma after it had created a sleeveless shirt for Cameroon's 2002 winning Africa Cup of Nations campaign. FIFA banned the radical design from that summer's World Cup, but Puma made headlines again two years later when they created an all-in-one shirt to prevent shirt-pulling. FIFA fined the Cameroon FA 200,000 Swiss francs and deducted six points from their World Cup qualification campaign -- although the punishment was revoked after Puma and Cameroon took legal action.

FIFA also states that no item of playing kit can be worn if the governing body considers it to be "dangerous, offensive or indecent," including "political, religious, or personal slogans, statements, or images." That has not stopped national teams from making strong statements.

Hummel unveiled a "toned-down" version of Denmark's shirt for this year's World Cup to protest against Qatar's reported mistreatment of migrant workers. Meanwhile, Ukraine's home shirt at last year's European Championship featured a map of Crimea, the Russian-annexed territory recognised as being part of Ukraine, which angered Russian officials.

Leaks, launch day and fan revolts or sales booms

After a design is finalised, a launch date is set and designers wait to see how their creations will be received by the public. Shirt designs are regularly leaked in advance, although this can actually be of benefit to brands looking to generate excitement before a big unveiling.

"It probably adds to the hype and the fan expectation, and that's not a bad thing," the anonymous former Nike brand lead told ESPN. "There's too many pieces of kit and inventory that are out to retailers, that are getting photographed, to be able to stop those leaks."

With the shirts out, designers must run the gauntlet of social media -- as shown by the less-than-glowing reception for many of this tournament's designs.

"You've got to be really respectful of the history and the fans as well," Buglass said. "Because if you're turning up with a colour that's completely off-kilter, all that's going to happen is the fans are going to revolt."

The success of a shirt is often tied to a team's success at a major tournament -- but not always. When a free-flowing Brazil side led by Pele won the first World Cup to be televised in colour in 1970, a generation of fans fell in love with the team and their canary yellow strip. By contrast, Nigeria's group-stage exit in 2018 seemed incidental after their colourful design sold out rapidly following its release.

"If you build an emotional connection with fans in instances like this, then they're going to want to wear that shirt with pride as well," the former Nike brand lead who preferred to remain anonymous said, referring to the "story-telling" behind that shirt.

Fans remember moments of World Cup glory, however, and brands know how to play on that connection to the past. Chris Stride, an academic from the University of Sheffield who has researched nostalgia in football shirts, says that brands began to appeal to adults' early memories of the game as a way of selling their products to an older generation from the 1990s onwards. It is a cycle which continues to this day.

"Nostalgia with international shirts is more likely to be about shared moments," Stride said. "When you have an international tournament, your family tend to watch, people who aren't into football tend to watch... There's a collective memory as much as an individual one."