Prime Minister Boris Johnson, the English Football Association and the Premier League have agreed to take "whatever action necessary" to stop the formation of the European Super League.
The PM told a round table discussion on the issue that the government "will not stand by while a small handful of owners create a closed shop", and suggested new laws could be brought in to block the breakaway competition.
" He reiterated his unwavering support for the football authorities and confirmed they have the government’s full backing to take whatever action necessary to put a stop to these plans," Number 10 said.
"He was clear that no action is off the table and the government is exploring every possibility, including legislative options, to ensure these proposals are stopped."
It is understood he told the meeting that the government should "drop a legislative bomb... now" to prevent the breakaway league.
The PM did not reveal exactly what he meant by the comment when asked at Tuesday evening's Downing Street press conference, but reiterated that the Government stood ready to legislate if there was no other way to stop the plan.
"That remains something that we will bring to the forefront if we have to," he said.
"What we want to do first of all is back the FA, back the Premier League, and hope that we can thwart this proposal before it goes very much further."
The so-called Big Six of the English Premier League faced a furious backlash after the unveiling of proposals for the Super League.
All 14 top flight teams not involved in the breakaway competition have "unanimously and vigorously rejected plans for the competition" in a meeting with the Premier League and other football authorities, including the FA, the Players' Football Association and the League Managers' Association.
A statement from the Premier League following the meeting said all those in attendance agreed they would urge the clubs involved to "cease their involvement immediately".
Downing Street did not rule out stopping players of clubs involved in the league getting work visas or withdrawing police funding for match days.
Asked about the suggestions, the Prime Minister's official spokesman said: "All these options are on the table at the moment.
"We will be working both to see what options are available to Government and we will be speaking direct, as the Prime Minister has done this morning with the Premier League, FA and others to see what collective action might be possible here."
The Prime Minister promised football fans prior to Tuesday’s meeting he will do everything possible to give the “ludicrous” new league a “straight red”.
Writing in The Sun, the Prime Minister said he was “horrified” at the implications for clubs up and down the country which had a “unique place” at the heart of their communities.
In a direct message to fans, he said: “It is your game – and you can rest assured that I’m going to do everything I can to give this ludicrous plan a straight red.”
What has the reaction been?
The plan involving England's richest clubs to breakaway from the Premier League has been roundly condemned, with even the Duke of Cambridge among those expressing outrage.
There's been an attempt to defend the proposed league by some of those involved, with Real Madrid president Fiorentino Perez saying it is “for the sake of football", but even players and managers at the clubs involved have spoken out against it.
Manchester City manager Pep Guardiola, who also used to manage Barcelona, said on Tuesday: “It is not a sport where the relation between effort and success does not exist.
"It is not a sport where success is already guaranteed, it is not a sport where it doesn’t matter when you lose.”
Liverpool’s manager Jurgen Klopp has previously spoken against the idea of a breakaway European league and told Sky Sports his views have not altered. “It didn’t change. My opinion didn’t change,” he said ahead of the game at Leeds. “I heard the first time about it yesterday and when you are trying to prepare for a difficult game against Leeds, we got some information, not a lot, most of things you can read in newspapers or wherever. “It is a tough one, people are not happy with that. I can understand that, but I cannot say a lot more about it because we were not involved in any processes – not the players, not me.
Liverpool captain on the night James Milner was unequivocal when asked for his views on the competition. “I can only say my personal opinion, I don’t like it and hopefully it doesn’t happen. I can only imagine what has been said about it and I probably agree with most of it,” he told Sky Sports.
The Duke of Cambridge – who is the president of the Football Association – spoke of the “damage” the plan would do to the national game.
FIFA president Gianni Infantino said on Tuesday his organisation - the highest governing body of association football - strongly disapproved of the plans.
He told the UEFA Congress: “We can only strongly disapprove the creation of the Super League, a Super League which is a closed shop, which is a breakaway from the current institutions, from the leagues, from the associations, from UEFA and from FIFA.
“There is a lot to throw away for the short-term financial gain of some. They need to reflect, and they need to assume responsibility.”
Everton FC said the plan amounts to "preposterous arrogance" which is "not wanted anywhere in football outside of the clubs that have drafted this plan".
There were protests outside grounds around the country on Monday at the scheme put forward by Liverpool, Manchester United, Manchester City, Chelsea, Arsenal and Tottenham together with six leading Spanish and Italian clubs.
Fans of both Liverpool and Leeds gathered outside the Yorkshire club’s Elland Road stadium before their evening fixture while a plane flew overhead with a banner proclaiming “Say No To Super League”.
Uefa president Aleksander Ceferin has warned players who take part could be banned from representing their countries in the World Cup and Euros.
In the Commons on Monday, Culture Secretary Oliver Dowden said that in the first instance it would be for the football authorities to prevent the English clubs from going ahead with the Super League.
But he said that if they were unable to do so, the government would do “whatever it takes” to protect the national game.
He said they were examining every option “from governance to competition law to mechanisms that allow football to take place”.
Mr Dowden also announced that he was bringing forward a wider fan-led review of the game to be helmed by former sports minister Tracey Crouch.
Education Secretary Gavin Williamson told ITV News the government has given the six clubs the "yellow card".
"They need to change their approach and they need to do something different. If they don't do that then the government will look at taking action, including competition law, to ensure they're not able to proceed in the way that they're proposing."
He added: "This is our national game, it came from England, it was originated here and it's really important that people understand the responsibility for this country on the whole game."
The Duke of Cambridge, meanwhile, tweeted to say he shared the concerns of fans about “the damage it risks causing to the game we love”.
“Now, more than ever, we must protect the entire football community – from the top level to the grassroots – and the values of competition and fairness at its core,” he said.
What exactly is being proposed?
The plan – which also includes the Spanish sides Atletico Madrid, Real Madrid and Barcelona and Italian clubs AC Milan, Juventus and Inter Milan – has support from investment bank JP Morgan, which will provide debt financing for the competition.
It is understood it will underwrite around six billion US dollars (£4.3 billion) in loans for teams involved.
It would see the breakaway teams create a competition to rival the Champions League, but it would not feature relegation or promotion.
Teams would play each other in midweek while still competing in their domestic leagues.