European football's 55 member associations have voted to boycott World Cups if the sport's governing body proceeds with a plan to sell stakes in its competitions to private investors.

The decision was made at an emergency meeting called to discuss the proposal announced earlier this week by Fifa, which oversees world football.

Concacaf, which governs football in North and Central America and hosted this year's World Cup, said its 41 member associations have "rejected" the proposal made by Fifa president Gianni Infantino, after it met on Thursday.

Sources say the Concacaf nations are also losing faith in Infantino.

Uefa, which governs European football, had already made its opposition clear by releasing two damning statements – and that strength of feeling has been reaffirmed.

"The World Cup cannot be treated as an investment product," it said on Thursday.

"It is one of football's greatest sporting legacies. It has been built over generations by players, national teams and supporters across every continent. No part of it should ever be surrendered to private investors. The World Cup is not for sale."

Uefa's boycott would cover all Fifa competitions, including the men's and women's World Cups and Club World Cup, and be triggered if Fifa president Gianni Infantino's proposals are voted through by member associations.

The first time this stance will be tested at a senior tournament is in October, when the Women's World Cup play-offs are due to be held.

It is understood FA chairwoman Debbie Hewitt and chief executive Mark Bullingham were among those to speak during Uefa's meeting, with the atmosphere described as venomous, such was the strength of feeling against the proposals.

Despite being one of eight Fifa vice-presidents, Hewitt had no knowledge of the discussions that Infantino had been having regarding the proposals.

Fifa wants to create a commercial subsidiary to run its main events, including its World Cups, and external investors will be able to buy stakes in it.

It said it would "invite third parties to make minority, non-controlling investments" in a new subsidiary – Fifa Forward Enterprise (FFE).

The plan needs to be passed by a vote of Fifa's 211 members.

Infantino needs 106 votes in favour for the proposal to go through. Uefa and Concacaf members combined make up 96 associations, who appear set to vote against.

Infantino has written to Fifa members saying they will receive $40m (£30m) if they back his controversial proposal. He has set a deadline of 19 September for federations to accept his plans if they want to access an initial $20m (£15m).

In a video released by Fifa on Wednesday, Infantino defended the plans, calling them "an offer, not an obligation".

If approval is granted, Fifa says Thrive Eternal is expected to lead the proposed investor group for FFE.

Thrive is an American venture capital firm founded by Joshua Kushner – the brother of US President Donald Trump's son-in-law Jared.

Fifa sources have told BBC Sport there has been no discussion over Infantino, or anyone else, becoming chief executive of FFE.

The White House said it had "nothing" to say on Infantino's proposals "at the moment".

In a statement released after Thursday's meeting, which was held virtually and chaired by president Aleksander Ceferin, Uefa said it and its 55 member associations "stand as one".

"We unanimously and unequivocally reject Fifa's proposal to transfer ownership interests in the World Cup and other Fifa competitions to private investors," it said.

On Wednesday, Uefa had accused Fifa of using football "to enrich themselves and their friends".

Its statement on Thursday was even more damning, calling it "irresponsible and indefensible that a proposal of such significance for football was conceived in secret" and "without any meaningful consultation" with those who steward the game.

It added: "This is not merely a profound failure of leadership, but an abdication of Fifa's duty as the custodian of world football.

"National associations around the world are now presented with an ultimatum: accept the irreversible capture of football's greatest competitions or bear the consequences.

"This is not a 'democratic decision', but governance by intimidation – an act of coercion unworthy of an institution entrusted with the stewardship of the global game."

While Uefa only accounts for a quarter of Fifa's membership, it does include most of the world's most successful teams.

Six of the eight quarter-finalists – including winners Spain – at this summer's World Cup were European. In the 2022 and 2018 editions, the figures were five and six respectively.

Of the 23 World Cups to have taken place to date, 13 have been won by European countries. The other 10 have been won by South American sides.

Uefa vice-president Laura McAllister said Fifa's proposals posed a "genuine existential threat to the game".

The former Wales international told BBC Radio Wales she hoped boycotts would not happen, adding: "I feel optimistic they won't, because the reality is the powerhouse of world football is Europe."

Speaking to Radio 4's PM programme, McAllister said there was "real unity" among Uefa members and an "easy consensus over the need to take the strongest possible action given the existential threat that the Fifa proposal poses to our sport".

She added: "The reality is we had no choice other than to issue a threat commensurate with this dreadful, catastrophic proposal that has been rushed through with no due diligence, no proper governance and no consultation."

A Football Association spokeswoman said England stood "shoulder to shoulder" with its European colleagues and "fully support the collective view".

She added: "We oppose Fifa's plans – the Fifa World Cup belongs to football and always will."

The Scottish FA added its support, saying its board "agrees unequivocally with the concerns raised by all members over the manner in which these proposals have been issued, and deadline set, without a full consultation process or consideration to good governance".

Scottish FA president Mike Mulraney is also the chair of Fifa's finance committee.

Culture Secretary Lisa Nandy said: "This is a principled decision that we strongly support. Football belongs to the fans, not billionaire investors. Enough is enough. It's time to take a stand to protect our game."

UK Prime Minister Andy Burnham criticised the plans on Tuesday, saying going ahead with the idea would mean Fifa had "sold out".

Concacaf said its members "expressed deep concerns about the lack of due process surrounding the proposal" and the "artificially short deadline imposed".

It also questioned the need for private investment after the most profitable World Cup in history, according to Fifa.

Concacaf added that it has tasked its Fifa council members with engaging the governing body on how to use existing reserves to fund development across the region and instruct Infantino to ensure proper governance processes are followed.

Ronan Evain – executive director of Football Supporters' Europe – told the BBC that Uefa's stance was "very impressive" and a "proper show of force".

He added: "It is the response that football needed – it is the response Gianni Infantino deserved."

The Asian Football Confederation said it was "disappointed" it had not been consulted before the plans entered the public domain.

The Confederation of African Football said its president Dr Patrice Motsepe would host a meeting of its executive committee next week to "assess and evaluate" the proposals.

The World Leagues Association (WLA) asked Fifa to withdraw its project and the Premier League, which is a WLA member, said it "wholeheartedly endorses" that view.

At this stage, there is a lot we do not know.

Fifa has been asked for a response to Uefa's statement. We do not know how it – and Infantino – will react.

We do not know what the implications will be for the Women's Under-20 World Cup, which is due to be held in Poland from 5 September – before Fifa's 19 September deadline for associations to claim an initial $20m payment by 1 January.

We also do not know what impact Thursday's news will have on Fifa's stated aim to bank the first tranche of 'private investment' cash by the end of October.

"I think on this occasion, Infantino's got to back down," former FA chairman David Bernstein told BBC Sport.

"This deal is not acceptable. If they want to raise capital, there's other, better, ways of doing it.

"In a normal organisation, if he has to back down on something of this magnitude, it would probably mean he'd be shown the door.

"But Fifa is not a normal organisation. If he has the support of enough of the national associations he will continue."

Without some sort of resolution, Uefa would be outside the global governance of the game.

However, Bernstein does not think it will come to that.

"I can't believe in the long term there will be a schism because it would be a lose-lose for everybody," he said.

"Fifa can't afford not to have European nations play in their competitions and frankly, Europe, also can't really afford not to be part of it."

There is no doubt in my mind this story equals that of the European Super League in being the biggest football has had to deal with.

Transfers are huge, but ESL and now this go to the very heart of what makes football the game it is and the structures that underpin it.

The logical conclusion to the involvement of private investment in Fifa competitions is that, eventually, they will be expanded, both in terms of size and frequency. That squeeze on the calendar would be felt all the way down the pyramids domestically and affect the structure of the game in every single country.

Uefa, which has been criticised itself for expanding its club competitions, knows it has the power to stop the Fifa plan.

A World Cup without European teams would rob it of three out of four semi-finalists from this summer's competition and six of the eight quarter-finalists. Three of the four semi-finalists in the last Women's World Cup were European. Three of the four semi-finalists in last year's Club World Cup were European.

If there are no European participants it is impossible to imagine Fifa generating the amount of revenue commercially needed to pay the sums it is offering.

It cannot be overstated how huge this story is.