One of the big concerns in modern football is the lack of protection for young local talent, in favour of foreigners, often of questionable quality.
Given that growing concern in the UK, the Planetfootball site decided to simulate the English top flight in FM2018 with a rule protecting local players.
The rule is simple: players without British nationality couldn't be used. The result? An unpredictable final table, more transfers between divisions and shocking results.

Setup

As mentioned, no team could use foreign players in their matchday squads, although they still appeared in their squads.
The transfer market felt the effect of the rule greatly, with an immediate rush for the best players who met the requirements; not only that, the game's artificial intelligence would try to get round the problem through nationality applications by players who had been settled in Her Majesty's lands, for many years.

For example, Daniel Sturridge would move to Man City for £57M, who would also sign Ben Davies from Tottenham, while Juan Mata (with a British passport) would move to Arsenal.
The Spurs to cover the departure of their left back, signed none other than James Milner to play on that flank. Aston Villa would use much of their budget on Mason Holgate (£40M) from Everton, who would use that money to sign James Ward-Prowse from Southampton.
Manchester United, Leicester and Huddersfield stayed out of the market.

End of the first half of the season and winter window

Manchester United and Tottenham comfortably led a table sunk in chaos.
Bournemouth third, while Arsenal, City and Chelsea fought fiercely….for 11th place in the table.
Yes, Abramovich's side, which had sacked Sarri, was battling for a mid-table place alongside two other title contenders; however, the naturalised English Belgian, Hazard, topped the league's ratings table, with an average of 8.13.
Huddersfield felt the new rule most, managing only 2 points in 14 games.

Guardiola, who would be replaced by Simeone right after the winter window closed, would invest £57M in Zaha; Ramsey would go to the Toffees for £50M and Southampton would pay £48.5M for Matt Phillips from West Brom.
Unai Emery would also be sacked and replaced at the Emirates by Ancelotti, after falling to 16th in the table.
Mourinho, despite leading the league, would be the one to loosen the purse strings, signing James Tarkowski, Kieran Tierney and Scott Arfield for £93M.

End of season

The Special One, unlike what has been happening in reality, easily wins England's top trophy, with 90 points.
Tottenham and their batch of Englishmen, initially one of the big title contenders, finished second with only a one point lead over Burnley, while Leicester missed out on the last Champions League spot on goal difference, by one goal, to Liverpool.
In last place, Huddersfield got their only win of the season in the final round.

Despite the protectionism the rule was meant to bring, foreigners still dominated the league, with Agüero, Lukaku and Giroud topping the scoring charts, while Hazard was named player of the competition. It makes us think the rule introduced isn't enough, and that all foreigners would actually need to be removed from the squads.