Plans for a Super League announced by 12 of European football's most powerful clubs plunged the game into an unprecedented crisis on Monday as the UK government threatened to invoke competition law to block a breakaway.
Six Premier League teams -- Liverpool, Manchester United, Arsenal, Chelsea, Manchester City and Tottenham Hotspur -- joined forces with Spanish giants Real Madrid, Barcelona and Atletico Madrid as well as Italian trio Juventus, Inter Milan and AC Milan to launch the competition.
They plan to leave the UEFA-sanctioned Champions League and start their new tournament "as soon as possible", with plans for three more founding members to join and five other clubs to be invited annually.
The competition threatens to completely upturn the world's biggest sport and leaves the prestigious Champions League -- itself the fruit of the last major shake-up in European football in 1992 -- facing an uncertain future.
Britain's culture secretary Oliver Dowden said the English clubs could find themselves subject to a formal review under British anti-trust law, which prevents the formation of monopolies or corporate cartels.
"We will put everything on the table to prevent this from happening," the minister said, vowing a "very robust response".
The breakaway announcement came just hours before UEFA announced a new format for the Champions League, which had been conceived to placate the continent's biggest clubs.
European football's governing body is pressing ahead with the new format from 2024 onwards, which will see the number of clubs involved increase from 32 to 36 with each team guaranteed 10 games.
UEFA president Aleksander Ceferin lashed out at the breakaway plan, calling it a "disgraceful self-serving proposal from a select few clubs purely fuelled by greed".
The Slovenian added that European member associations were "all united against this nonsensical project" and said players involved would not be allowed to play for national teams, effectively banning them from taking part in European Championships and World Cups.
However, organisers of the Super League said they would file a motion "before the relevant courts" to stop players being banned and "ensure the seamless establishment and operation" of the competition, according to a letter seen by AFP, addressed to Ceferin and FIFA chief Gianni Infantino.
The breakaway league is being backed by US investment bank JPMorgan, which confirmed to AFP that it was "financing the deal".
The founding clubs will share 3.5 billion euros ($4 billion, £3 billion) for infrastructure investment and to offset pandemic costs, and are expected to receive a further 10 billion euros in "solidarity payments" over the life of the initial commitment -- much more than in the current Champions League.
The 15 eventual founders will be guaranteed to play each year in a competition intended to take place in midweek, allowing clubs in theory to continue participating in domestic leagues.
"One thing I understand and that people think is not right is the competitiveness," said Liverpool manager Jurgen Klopp, who confirmed he was not consulted on the proposals.
The absence of French and German teams from the founding members is notable, despite Bayern Munich and Qatar-owned Paris Saint-Germain reaching last season's Champions League final.
Bayern have distanced themselves from the project, with chairman Karl-Heinz Rummenigge saying: "We are convinced that the current structure in football guarantees a reliable foundation."
However, a source close to the 12 founding clubs told AFP "at least two French clubs" are set to be involved every year.
The reaction from fans and pundits across Europe has been furious.
"It's the death of football... Football is based on the concept of competitive balance, sporting competition and qualifying on merit," Tim Payton, head of the Arsenal Supporters Trust, told AFP.
Supporters from both Leeds and Liverpool protested outside Elland Road ahead of Monday's Premier League match.
Players have also voiced their disapproval.
"I can only say my personal opinion, I don't like it and hopefully it doesn't happen," said James Milner, who captained Liverpool on Monday.
Under the plan, two groups of 10 will play each other home and away, with the top three qualifying for the quarter-finals. The fourth and fifth-placed teams would play off for the two remaining spots.
Then the competition would adopt the same two-leg knockout format used in the Champions League before a single-leg final in May.
World governing body FIFA expressed its "disapproval" and called on all parties "to engage in calm, constructive and balanced dialogue".
The Premier League, the richest in Europe, issued a furious statement to say "the concept of a European Super League would destroy" the dream that any team could "climb to the top and play against the best".
The powerful European Club Association said it "strongly opposes" the plans after its own chairman, Juventus supremo Andrea Agnelli, stepped down.
Having been heavily involved in negotiations with UEFA over a new Champions League format, Agnelli came in for stinging criticism from Ceferin.
"I've never seen a person that would lie so many times, so persistently as he did. It's unbelievable," Ceferin said.
But Real Madrid chief Florentino Perez, who was announced as the first Super League president, said the breakaway reflected the big clubs' wishes.
"Football is the only global sport in the world with more than four billion fans and our responsibility as big clubs is to respond to their desires," he said.