Disciplinary proceedings have been opened against Real Madrid, Barcelona and Juventus in connection to their involvement in the aborted European Super League, UEFA has announced.
The three teams were the only ones of 12 original breakaway clubs who did not subsequently renounce the competition and reaffirm their commitment to UEFA.
A UEFA statement read: "Following an investigation conducted by UEFA ethics and disciplinary inspectors in connection with the so-called 'Super League' project, disciplinary proceedings have been opened against Real Madrid CF, FC Barcelona and Juventus FC for a potential violation of UEFA's legal framework."
UEFA had previously opened a disciplinary investigation with regard to a potential violation of the governing body's legal framework by the three clubs concerned.
The nine other clubs, including six from the Premier League, committed to the existing national and international competitions, with the threat of heavy fines and expulsion were they to renew their interest in the breakaway project.
But Real Madrid, Barcelona and Juventus not only failed to follow their lead, but issued a joint statement standing by the prospective competition and its legal standing.
UEFA's move raises the prospect of the three clubs being sanctioned, with some reports suggesting they face expulsion from UEFA competitions such as the Champions League for a period of two years.
