However UEFA have now confirmed that on that precise accusation Mourinho has no case to answer.

UEFA director of communications William Gaillard said: “UEFA have never said that Mourinho caused Frisk to resign. This is a big logical jump. All we’re saying is that some statements from managers and players are misconstrued by the public at large who are not mentally stable.”

The behaviour of the former Porto boss remains under investigation, however, and his conduct in Barcelona will be considered by UEFA’s control and disciplinary body next Thursday, March 24.

Mourinho suggested that Frisk met with Barcelona coach Frank Rijkaard in his dressing room at half-time in the first leg of Chelsea’s last-16 tie at the Nou Camp.

Frisk chose to retire after his family’s safety was called into question by the anonymous threats.

Chelsea are facing possible fines for failing to show for the Nou Camp post-match press conference and for sending their players out late for the second half of a game they lost 2-1, before turning the tie around at Stamford Bridge.

“It was never Mourinho’s intention to whip up feeling against Frisk, but we would ask all managers to be careful and refrain from making these statements,” said Gaillard.

“No-one at UEFA has linked Mourinho’s comments with the resignation of Anders Frisk. This is not on the agenda for our next executive committee meeting, but I’m sure there will be a general discussion on how we can protect referees.”

Gaillard’s statement is a sign of UEFA’s desire to improve relations with Chelsea after a difficult period.

European football’s governing body yesterday distanced themselves from comments made by their head of refereeing Volker Roth.

The German has been widely quoted as describing Mourinho as an “enemy of football”, although UEFA feel his comments were misinterpreted.

UEFA seem ready to renew their previously solid working relationship with the Londoners ahead of tomorrow’s Champions League draw.

Gaillard added: “Of course we want to have a good relationship with Chelsea. No-one becomes a pariah. When the Chelsea delegation come for the draw tomorrow they will warmly received by us.”

Meanwhile, Iain Dowie has come to the defence of Mourinho, claiming he is football’s friend.

The Crystal Palace manager will face Mourinho for the second time this season when he takes the Eagles to Chelsea on Saturday.

Dowie said: “We have had managers talk about referees since time immemorial. I don’t think we should lose sight of what Jose has achieved as a manager. I don’t think he is an enemy of football. I think the opposite. He is a manager who is absolutely serious about his art. I have found Mourinho very respectful.”