The conversation took place between the head of insurer Unipol and PieroFassino, who was the leader of the biggest centre-left party and Mr Berlusconi's biggest political rival at the time.
It was backed, first, by Mr Prodi's deputy prime minister, Francesco Rutelli, and then by PieroFassino, boss of the biggest party in the government, the ex-communist Democrats of the Left.
PieroFassino has switched from foreign trade to the much trickier job of justice, while a former trade unionist, Ottaviano Del Turco, has moved from the parliamentary committee that deals with the Mafia to be finance minister.