Why UEFA snapped

The nature of Chelsea's complaint was confirmed a few hours after the game when the club claimed Barcelona coach Frank Rijkaard had been seen leaving referee Anders Frisk's dressing room during the halftime interval.

Clarke was pinpointed as Chelsea's key witness in the affair and the club submitted a report to UEFA which purported to provide evidence of their grievance.

At the same time, Mourinho continued to attack Frisk's handling of the game and also refused to distance himself from the claim the referee spoke with Rijkaard.

In a dramatic twist, Frisk then announced his premature retirement from refereeing, citing death threats that he had received from Chelsea supporters.

Mourinho was branded the "enemy of football" by UEFA referees' chief Volker Roth with the implication being that his comments were to blame for inflaming passions.

In recent days, there appeared to be a thaw in Chelsea's battle with the authorities after UEFA claimed Roth's views were personal rather than an official standpoint. The club's chief executive Peter Kenyon also met with UEFA chief executive Lars-Christer Olsson in a bid to find an amicable solution.

Today, however, the conciliatory mood has been shattered by UEFA's lengthy charge sheet which could lead to a raft of disciplinary sanctions imposed on the club.

The ultimate punishment could see Chelsea thrown out of the Champions League, but observers suggest fines and touchline bans for the central figures are more likely.

At the centre of the case will be the five minutes or so which followed Frisk's half-time whistle. Chelsea claim Frisk and Rijkaard walked along the tunnel together before the Dutch coach went into the official's dressing room.

Clarke is said to have watched events unfold from a glass partition at the end of the Nou Camp tunnel, even though independent sources say the view from there would be inconclusive.

In addition to Frisk's own version of events, their lead media officer Fritz Ahlstrom has given evidence saying that Rijkaard's exchange with the referee-involved little more than a polite hello and welcome to Barcelona.

In fact, UEFA claim Ahlstrom, who is Danish, was walking along the tunnel with Frisk when Rijkaard briefly came up to speak to him. They refute entirely the suggestion that he later went to his dressing room.

At a hearing on 31 March, UEFA will back up their charges with Frisk's report and evidence from their own delegate at the match.

The club are certain to fight the new charge vehemently.

Now UEFA will attempt to have the final say in an attempt to silence Mourinho and also send out a message to other managers about the sanctity of referees.