Manchester United, Liverpool, Arsenal, Chelsea, Tottenham Hotspur and Manchester City are among 12 European teams who have signed up in theory to a breakaway "Super League". The deal would mark the greatest revolution in European football since the 1950s, and could kill the lucrative Champions League, which was on Monday due to announce plans to increase in size. With battle lines now drawn for a sport in civil war, Telegraph Sport explores they key questions and themes. What has happened? England's so-called "big six" signed up with six other European teams for a plot which would change the game as we know it. Initially spearheaded by Barcelona and Real Madrid, the proposed new competition could generate £3.1 billion for the first 15 members. To put that into context, Uefa currently distributes about £3 billion in prize money and television broadcasting deals to clubs participating in all its European competitions each year. Secret talks have been taking place for years about generating a bigger prize pot for the biggest teams, but a plan has accelerated since last autumn. A scheme underwritten by US investment firm JP Morgan would involve an NBA-style format, releasing an "infrastructure grant” ranging from £310 million to £89 million per club involved to cover losses during Covid-19. As well as the six English and two Spanish clubs, Atletico Madrid, Juventus, AC Milan and Inter Milan have also signed up — but not Bayern Munich, Borussia Dortmund or Paris St Germain. Why now? The proposals appear to be an 11th-hour bid to derail sweeping Champions League reforms due to be rubber-stamped from 2024. That deal had already been branded by fans as an "indefensible" power grab due to increased matches and revenue for the top clubs but Ed Woodward, executive vice-chairman at United, and Ivan Gazidis, chief executive of Italy’s AC Milan, were known to have objections over commercial arrangements. Uefa had been confident that the current changes to the format of the Champions League from 2024 were enough to see off a breakaway, having drawn up plans to guarantee more fixtures and – most controversially – more certainty that the biggest clubs would be involved in the lucrative competition in the first place. But, while clubs on Friday gave the governing body the green light to approve the plan on Monday, concerns remained among the giants around media and sponsorship rights. Under the last offer from Uefa, 51 per cent ownership would remain with the governing body, with the rest controlled by the European Club Association. Two sources close to talks told Telegraph Sport that final negotiations were still taking place around commercial arrangements, so the confirmation of intention to break away, Uefa hope, is a final negotiating tactic. How will the new competition work? Broadcaster DAZN, which is owned by billionaire Len Blavatnik's Access Industrie, is also understood to be involved. Proposals have included a 20-team league, made up of 15 permanent members and five who would qualify annually. This format would see two groups of 10 clubs, with the top four from each group going through to a knockout phase that would be similar to the current Champions League. Matches would still be midweek and could continue alongside traditional domestic competition. The main advantage for the 15 founders is guaranteed entry – and the revenue that goes with it – each year. Even with the proposed changes to the Champions League, there remains a possibility teams could fail to qualify. THe proposed European Super League would eliminate that risk. Will the Champions League reforms still take place? On Monday, Uefa delegates were due to rubber-stamp the plans from 2024 — but it is possible a late offer may be tabled to keep the big clubs happy. As it stands, European football’s elite club competition increases from 32 teams to 36, with the total matches played from 125 to 225 from 2024/25. Of the four extra places, one would go to the league rated the fifth-strongest in Europe, with another going to the highest-ranked domestic champion from one of the smaller leagues. The remaining two go to the clubs with the highest Uefa coefficient (historic ranking), meaning the likes of Liverpool could finish as low as seventh in the Premier League and still qualify. The group stage undergoes a complete overhaul, with each team playing five home matches and five away matches against 10 different opponents. Every team is seeded and plays opponents of varying strength under the ‘Swiss system’, a format pioneered by chess and since adopted by other sports. How has football reacted to the Super League plot? Almost universal condemnation from everyone but the clubs involved. Gary Neville, the former Manchester United and England defender, was among those outraged by plans which could cause untold financial damage to smaller clubs - but create billions more for the top clubs. "I'm a Manchester United fan and I have been for 40 years of my life but I'm absolutely disgusted," he told Sky Sports. "I'm disgusted with Manchester United and Liverpool most. Liverpool, they pretend 'You'll Never Walk Alone', the people's club, the fans' club. Manchester United, 100 years borne out of workers round here, and they're breaking away into a league without competition, that they can't be relegated from? It's an absolute disgrace." The Premier League described it as “deeply damaging” and urged clubs involved to “walk away immediately before irreparable damage is done”. The Football Association echoed those sentiments and added that it would “take any legal and/or regulatory action necessary to protect the broader interests of the English game”. A further joint statement from those organisations, in conjunction with Uefa and the leagues and national associations of Spain and Italy, said it was a “cynical project” that was “founded on the self-interest of a few clubs”. It added: “This persistent self-interest of a few has been going on for too long. Enough is enough.” The clubs themselves have not commented. Who are the key players, and what are they doing? The rebel 12 For Real Madrid's president Florentino Pérez, it is third time lucky. The plan he has championed for years finally looks set to be get off the ground. Gaining support from the likes of Manchester United, Liverpool, Arsenal, Chelsea, Tottenham Hotspur and Manchester City comes after similar plots had fallen flat following cold feet from executives. Similar schemes had been detailed in the Football Leaks scandal more than two years ago and then in December 2019, when Fifa denied being supportive of the idea after it emerged they had held talks. This time Perez seized upon Covid-19 turmoil and the fall-out surrounding Project Big Picture last autumn to entice the elite to join him in signing up for the most significant restructuring of elite European football since the 1950s. Rest of the Premier League Everton, West Ham and Leicester City are among clubs with the most to lose in Europe. Those just outside the established "big six" are left between a rock and a hard place, already fuming over Champions League reforms from 2024 which provide safety-net qualification for historically successful clubs. The prospect of being frozen out of elite European football forever will almost certainly affect the amount that the smaller clubs will generate from the next domestic TV rights sell-off, which has been due to be launched by the Premier League within weeks. Those without a chance of making the five spare places across Europe for the Super League each season would see their finances shrink rapidly. The Premier League as an institution Barely six months since England's top tier saw off Project Big Picture, a European breakaway presents a threat almost as fundamental. After crisis talks between executives on Sunday morning, the league said the plot would destroy the "dream" for teams like Leicester becoming champions. Domestic leagues would have to ratify the new competition for it to be launched, and it seems unfathomable that the big six will be able to persuade the other clubs that it should be voted through. Money talks, however, and one option for the clubs involved will be to pass on a fraction of the enormous profits they stand to make in a deal that sees the 15 founding clubs extract 32.5 per cent of all revenue. This time Premier League HQ believes its best hope of torpedoing the deal is in combining forces with other domestic competitions as well as international governing bodies. "We will work with fans, The FA, EFL, PFA and LMA, as well as other stakeholders, at home and abroad, to defend the integrity and future prospects of English football in the best interests of the game," the league vowed on Sunday night. Uefa Since October, Uefa executives had scoffed at the idea that European giants were serious about their plan. Breakaway threats arrive like clockwork at times when Champions League reforms are being discussed, they said. Uefa plans to increase the size of the Champions League from 2024 already represented the biggest transformation of the European game in decades. But the evidence has been there in recent weeks that the big clubs still were not satisfied that profits were being maximised. Ed Woodward, executive vice-chairman at Manchester United, and Ivan Gazidis, chief executive of Italy’s AC Milan, last month raised objections to the commercial arrangements, and it seems a Uefa offer of 49 per cent in voting share to the European Club Association was not enough to derail the breakaway threat. The Champions League would implode without its biggest teams, and Uefa were quick to up the ante on Sunday by telling the breakaway gang that they will take them to court if the plot goes any further. "We will consider all measures available to us, at all levels, both judicial and sporting in order to prevent this happening," the governing body said. "Football is based on open competitions and sporting merit; it cannot be any other way." Fifa In terms of undermining the rebellion, it is football's global governing body that may yet have the most power in turning the planet's best players against the plan. Despite previously holding talks with the plotters, Fifa has come out against the threat, and warned players that they would no longer be allowed to compete in the World Cup.