As one international media tycoon was flying to London to deal with the crisis in his empire, another cut short a visit to the Mediterranean island of Lampedusa and hastened to Rome after being dealt the heaviest blow yet in his controversial business career.

Silvio Berlusconi learned on Saturday that judges in Milan had ordered his company Fininvest to hand over more than half a billion euros to his deadliest rival.

The money is compensation for bribery of a judge to rule in Berlusconi's favour in his struggle with the industrialist Carlo De Benedetti for control of Mondadori, Italy's biggest publishing house.

Last week it was discovered that a clause had been inserted in a package of budgetary adjustments that would have meant Fininvest did not have to pay the compensation until it had exhausted the appeals process. In Italy, that can take years, or even decades.

Several ministers have since said they knew nothing about the insertion until it was reported in the media. But the prime minister has insisted it was discussed in cabinet.

Berlusconi himself was put on trial for bribery in connection with the Mondadori judgment, but the charges against him were dropped in 2001 after being timed out by a statute of limitations. In their written ruling, however, the Milan appeals court judges said he was "jointly responsible" for the corruption.

They said it was "beyond any plausible reasoning" that Fininvest's lawyers would have been given the money to bribe the judge while "the owner of the company that paid and benefited was kept in the dark". It was obvious they would not have acted "in the absence of an unequivocal order" from Berlusconi, the judges said.

The prime minister had not given any reaction to the sentence by Sunday afternoon. But his daughter Marina Berlusconi, president of Fininvest, told the Corriere della Sera newspaper the case would be taken to Italy's highest appeals court. "My father has never anything wrong," she said. She noted that the 1991 ruling at the centre of the dispute was underwritten by three judges, only one of whom was subsequently convicted of accepting the bribe.

A lower court had fixed the compensation at €750m. The Milan appeals court reduced the figure to €560m. Marina Berlusconi said the lower figure was still out of all proportion. Fininvest's 50% holding in Mondadori, she said, was worth less than half that amount.

The Mondadori group includes nine publishers and more than 40 magazines including the news weekly Panorama and the Italian edition of Cosmopolitan.