Chelsea and three of their star players, Didier Drogba, Michael Ballack and Jose Bosingwa are likely to be charged following the ugly scenes at the end of Wednesday's 1-1 draw with Barcelona.

UEFA have been studying the report of referee Tom Henning Ovrebo after the second leg of the Champions League semi-final.

The Norwegian turned down four penalty appeals from the Blues and was then subjected to abuse from Ballack during the match and Drogba once the final whistle had gone.

Bosingwa then added his voice by labelling the official a "thief" on Portuguese television.

All three may be in the dock as will Chelsea, themselves, for failing to control their players. Drogba's antics could cost him more as the club are now considering selling him in the summer.

The Ivory Coast star has one year left on his contract but the Chelsea hierarchy are once again understood to be willing to listen to offers. They were keen to sell him last year after he was sent off in the Champions League Final against Manchester United only for no bids to be forthcoming.

He was in line for a new deal in light of an impressive run of form since Guus Hiddink took over as manager in February but those plans are now on hold.

The club will not sell the 31-year-old on the cheap and value him at £15million, which could scare a number of potential suitors off in light of his age, knee injury problems and his temperament.

But Manchester City and Inter Milan have admired him for some time and are expected to still make him one of their targets for the close season.

Wherever he is playing his football next term, he is set to start the campaign suspended from European competition.

Drogba and Bosingwa both tried to limit the damage last night by issuing public apologies.

"I was very upset at what happened during the game but having seen the pictures on TV I accept I overreacted," said Drogba

"I regret that in the heat of the moment I let out my incredible frustration and disappointment in this way and for that I apologise.''

Bosingwa added: "We were all very frustrated after the game but I regret describing the referee as a thief. Having had some time to reflect I would like to withdraw those comments."

But UEFA have taken a dim view and are ready to take a firm stance. General secretary David Taylor said: "When we get to the top level we expect better in terms of players' behaviour.

"Refereeing is an extremely difficult job. All I would ask is a bit more respect is shown towards officials.

"Notwithstanding the high emotions, high drama and high stakes involved, these guys are out there having to make decisions just like that, on the spot.

"I spoke to [the Chelsea chief executive] Peter Kenyon at the end of the match and he fully accepts there are no conspiracies at all.

"Of course there are questions from time to time about refereeing standards but that's looked at continually in terms of performances. That's what we do as a responsible organisation."