The list of players potentially at risk of losing the right to play in Britain includes two of the undoubted stars of the Premier League season: Leicester City's N'Golo Kante and West Ham's Dimitri Payet, although both played and scored for France this week.

West Ham vice-chairman Karren Brady, the face of the Britain Stronger in Europe campaign, has already written to club bosses throughout the UK warning them a vote to leave would have "devastating consequences".

Premier League boss Richard Scudamore made it clear in a speech to the Institute of Directors last year that his personal view was that Britain should stay in the EU, the world's largest trading bloc.

However, the Premier League's public position is that EU membership is a matter for voters and it always works with "the government of the day".

Privately, the league believes it is almost impossible to know what the situation regarding overseas players would be if the UK votes to leave. It is a stance shared by the Football Association.

The government, for example, could bring in a quota system similar to former Fifa president Sepp Blatter's "six plus five" idea, or it could indeed open the possibility of doing bilateral deals with the likes of Argentina and Brazil to make it easier for their players to work here.

Prior to this season, players without an EU passport were meant to have played in 75% of their national side's competitive games over the past two years.

This only applied to nations ranked in Fifa's top 70. However, appeals were allowed for talented players from lower-ranked sides as well as players who may have missed international call-ups because of injury.

The new rules, brought in after hard lobbying by the FA, were intended to strike a balance between a club's desire to hire the best available and the need for more openings for young British players.

"I would be surprised if those work permit rules were not recalibrated," said Professor Raymond Boyle, from the University of Glasgow.

The sports industry expert added: "Countries such as Switzerland simply make their own rules. My sense is that elite commercial sport will always have the clout to influence rules so that they benefit."

What everybody agrees on, though, is that British football would be in for a period of flux as new rules were decided and clubs rebalanced their squads.

"This could be a positive thing for home-grown players in the longer term," said leading agent Simon Bayliff.

"The downside could be the value of the Premier League decreasing, as its attraction is the collection of foreign stars across many clubs.

"I don't personally believe it will have a huge impact on the biggest names but it could have an effect on the general traffic of non-star international players, which may hurt the league's quality and attractiveness to foreign investors.

"But all this depends on how we Brexit - and that is impossible to predict."