A host of star players would not have played in the Premier League last season had the United Kingdom already left the European Union, according to investment banker Keith Harris.
Harris, who has helped oversee the sale of numerous football clubs including Chelsea and Manchester City, told Sky Sports News HQ that N'golo Kante, Anthony Martial, Romelu Lukaku and Dimitri Payet would not have been allowed to join their clubs.
Currently players from countries within the EU can work in Britain without a work permit but that is set to change following the vote to leave, although it is likely to be several years before the effects are felt.
Last season 432 European players were registered to play in the Premier League. Those players are unlikely to have to leave following the vote, but new players will not have an automatic right to live and work in the UK.
"It was a shock result," said Harris. "There are four players that we can reflect on and the impact they had on their clubs last year, who may not have been able to come in.
"Kante, who had a huge impact at Leicester, Martial at Manchester United, Lukaku at Everton and Payet at West Ham.
"I wonder how attractive the Premier League would have been and how well those clubs would have done without those specific players, and that's the kind of thing we are now speculating about."
Europeans could now be subject to the same immigration rules as non-EU players, under which a player from a top-10 nation has to have played in 30 per cent of their games in the two years prior to the date of application to be granted a work permit.
A player from a nation ranked 11-20 must have played in 45 per cent of international games and that percentage rises to 60 per cent for the next 10 countries, then 75 per cent for nations ranked 31-50.
However, Harris believes that anyone thinking of investing in a club in England could now find the prospect very attractive.
"If you're thinking of buying an asset in this country, then it's just cost a foreign investor overnight about 10 per cent less and that's attractive if they have confidence in the long-term future.
"We all knew an out vote would take two years to unravel. Gravity is a strong force in financial markets so when there is a shock, markets fall very steeply and take a while to climb back and that's what we're going to be seeing now. We're going to be treading water."
A Premier League spokesman admitted the referendum has created uncertainty but stressed the English top flight is expected to maintain its position at the pinnacle of the global game.
Their statement said: "The Premier League is a hugely successful sporting competition that has strong domestic and global appeal. This will continue to be the case regardless of the referendum result.
"Given the uncertain nature of what the political and regulatory landscape might be following the 'Leave' vote, there is little point second guessing the implications until there is greater clarity.
"Clearly, we will continue to work with Government and other bodies whatever the outcome of any process."
EFL chief executive Shaun Harvey added: "The ramifications of leaving the European Union may prove to be significant for every industry in the UK, including football. However, at this stage, it is fairly unclear what the precise impact will be on the EFL.
"Clubs were contacted earlier this morning in order to outline that we are engaging with the Government and the other football bodies to ensure that our sport's views are understood and taken into account during the discussions that lie ahead."