FIFA President Gianni Infantino on Tuesday warned that clubs involved in the European Super League could face "consequences," as the backlash built against the deeply divisive plans.
Infantino leant his support to European football's governing body as it attempts to quash an initiative that threatens its prized Champions League and the health of domestic competitions such as England's Premier League.
"It is our task to protect the European sport model, so if some elect to go their own way then they must live with the consequences of their choices," Infantino said at UEFA's congress in Switzerland. "They are responsible for their choices."
Twelve powerful clubs – six from England, and three each from Spain and Italy – have signed up for the Super League, which offers guaranteed spots for its founding members and billions of dollars in payments.
Liverpool, Arsenal, Chelsea, Manchester City, Manchester United and Tottenham Hotspur are the English clubs involved, together with Barcelona, Atlético Madrid and Real Madrid from Spain and Italian trio Juventus, AC Milan and Inter Milan.
Currently, teams have to qualify for the Champions League each year through their national competitions, and face a lengthy group phase before reaching the high-profile latter stages.
The Super League would guarantee a spot for its founding members every year, removing the uncertainty of qualification and the accompanying risks to revenue.
The breakaway plan prompted a furious reaction from fans and officials, with UEFA President Aleksander Čeferin saying on Monday it was motivated by "greediness, selfishness and narcissism", and Liverpool manager Jürgen Klopp saying its closed nature was "not right".
Klopp's Man City counterpart Pep Guardiola also came out against a closed competition, which he said is "not sport".
"It's not a sport when success is already guaranteed, it's not a sport if it doesn't matter if you lose," said the Spaniard.
On Tuesday, Čeferin implored club owners, particularly those of Premier League teams, to row back on the plans.
"There's still time to change your mind. Everyone makes mistakes," said the Slovenian. "English fans deserve to have you correct your mistake, they deserve respect."
Three more clubs are expected to sign up, including "at least two" from France, a source told AFP.
Qatar-owned Paris Saint-Germain are a notable absentee, while Bayern Munich, the reigning European champions, have distanced themselves from the project.
"Paris Saint-Germain holds the firm belief that football is a game for everyone," said PSG president Nasser Al-Khelaifi in a statement.
A serious threat
Five more clubs will qualify annually for the 20-team, midweek competition, where two groups of 10 will precede two-legged quarter- and semi-finals and a one-off final. The competition is due for launch "as soon as is practicable."
It constitutes a serious threat to UEFA, which together with the English, Spanish and Italian football authorities said the clubs could be banned from domestic and European competition.
The British government also said it was considering invoking competition law to block the breakaway.
Backed by US investment bank JP Morgan, the Super League is offering the founding clubs an initial pot of 3.5 billion euros (US$4 billion) for infrastructure investment and to offset pandemic costs.
The clubs, most of them heavily indebted and saddled with enormous player salaries, are expected to receive a further 10 billion euros in "solidarity payments" over the life of the initial commitment – much more than the returns available in the Champions League.
British Prime Minister Boris Johnson warned "no action is off the table" – including new legislation – to stop the European Super League after meeting with football chiefs and fan groups on Tuesday.
"The prime minister confirmed the government will not stand by while a small handful of owners create a closed shop," Downing Street said in a statement.
However, organisers of the Super League said they would file court motions to stop players being banned and "ensure the seamless establishment and operation" of the competition, according to a letter to Čeferin and Infantino that was seen by AFP.
Real Madrid president Florentino Pérez, the head of the new ESL, said it was "impossible" that clubs would be thrown out of the Champions League, whose upcoming semi-finals feature Chelsea, Manchester City and Real Madrid.
"Football has to keep changing and adapting to the times. Football is losing interest. Something must be done," Pérez said.
Real coach Zinedine Zidane said he "had an opinion" on the Super League but "would not give it", saying it was "a question for one man [Pérez]."
'Hopefully it doesn't happen'
Liverpool midfielder James Milner became the first player of one of the clubs involved to speak openly against the project.
"I can only say my personal opinion, I don't like it and hopefully it doesn't happen," Milner said after Liverpool's Premier League draw at Leeds on Monday.
Fans of both clubs protested outside Elland Road before the match, while Leeds players wore shirts featuring the Champions League logo and the words "Earn it" and "Football is for the fans" during the warm-up .
Liverpool manager Klopp was angered by Leeds staff leaving similar shirts in the away dressing room before kick-off.
Everton, Liverpool's Merseyside rivals, accused the Premier League's 'big six' of "preposterous arrogance" and said they were "acting entirely in their own interests".
The breakaway announcement came just hours before UEFA announced a new, 36-team format for the Champions League, which had been conceived to placate the continent's biggest clubs.