Sepp Blatter, the Fifa president, set English football yesterday on a path to a player quota system within three years. The head of football’s world governing body is determined to overcome opposition from the European Union to push through his radical plans to curb the number of foreign players in the English game and an independent report has appeared to advance his case.

The report, by the Institute for European Affairs (Inea), a Düsseldorf-based think-tank, was unveiled in Brussels yesterday and claimed that there was “no conflict in European law” to prevent the implementation of Blatter’s 6+5 rule, which would force teams to field at least six players who are eligible to play for the national team of that club. The European Commission, the executive body of the EU, has always warned that such a quota system would contravene EU law allowing free movement of workers.

Inea said, though, that the 6+5 rule was “legally not directly linked to the nationality of the footballer but applies to the qualification for the national team” and could be interpreted as simply being a law of the game.

“It can, therefore, at most, legally involve an indirect discrimination, which can be justified if there are compelling reasons in the general interest,” the think-tank said. “It has an important protective function for the whole of international sport.”

The findings were seized on by Blatter, who has stepped up his vigorous campaign for a quota, winning the backing of Fifa delegates for its introduction by 2012 but antagonising the Premier League, inevitably the most high-profile target of the idea.

“This study confirms that we are not breaching European law in defending the 6+5 rule,” Blatter said. “We want to encourage the development of young players, protect national teams and maintain competitiveness and the unpredictability of results.”

But the ink had barely dried on the Fifa-commissioned report when EU officials were saying that nothing had changed and that it could take a ruling by the European Court of Justice to convince them that his proposal was legal.

That will be music to the ears of Premier League executives, who remain opposed to any quota, although the Football League has approved a less controversial system that will demand at least four “home-grown” players in the matchday squad of 16, a system favoured by Michel Platini, the Uefa president. That means players can be of any nationality, as long as they have been registered in England for three years before their 21st birthday.

That scheme is little more than a toe in the water but Lord Mawhinney, the Football League chairman, believes that it could be extended to bring a more national feel to the English game and develop English talent, and he has the enthusiastic backing of Football League club chairmen.