The prospect of a repeat of the dramas of March, when Jacques Santer's team resigned en masse, arose from mounting anger among German centre- right MEPs, who feel cheated by the political make-up of Mr Prodi's team.
A dramatic debate saw the president sustain a furious attack by members of the assembly's biggest faction. That could come to a head in September when parliamentary committees vet individual commissioners in American- style confirmation hearings.
Confrontation blew up only minutes after Mr Prodi delivered a wide- ranging and populist speech to MEPs in their new, ultra-modern debating chamber.
Flanked by Neil Kinnock, the vice-president, and standing in front of his team of European commissioners, Mr Prodi outlined plans for a new, independent food and drug agency for Europe. Other ideas included an EU-wide solution to air traffic control crises, and intervention over doping in sport.
These initiatives won warm applause, as did an attack on EU states for squabbling over Kosovo reconstruction. But they were overshadowed by a swift and hostile counter- attack from Hans-Gert Pottering, chairman of the centre-right European Peoples Party (EPP), or Christian Democrats. He said bluntly: "We remain perfectly free to say `yes' or `no' to the Commission. We may decide not to give our approval to the Commission."
German Christian Democrats are furious that neither of their country's two commissioners comes from the centre-right, despite the gains made in the European Parliament elections in June.
Mr Pottering added: "We in the EPP group do not believe that this Commission is politically balanced. Therefore we should not allow the legend to emerge that this Commission is politically balanced."
The attack won applause from Jacques Santer, the Commission president who resigned in disgrace in March, only to win election as a Christian Democrat MEP in June.
The verbal assault took aback many colleagues, including Alan Donnelly, leader of the 30 British Labour MEPs, who described it as "appalling".
The EPP, with 233 MEPs, is the biggest political bloc and will play a leading role in hearings of commissioners in September, which precede a vote on the Commission as a whole.
A source close to Mr Prodi insisted that he would stand up to any attempt to challenge the make-up of his new team, unless there were objections of a "fundamental" nature against candidates. That would leave the parliament with the choice between approving the Commission or rejecting the nominations en masse.
However, EU officials and parliamentarians are sceptical that the EPP will go through with its threat. They predicted that the centre-right would split amid fears of the consequences of provoking another constitutional crisis for Europe. One official added yesterday: "MEPs have enough trouble trying to find their way to their offices, let alone evicting anyone else from theirs."
Yesterday MEPs, including the new president of the Parliament, Nicole Fontaine, appealed for the early publication of a second report by an independent committee set up to examine sleaze and cronyism in Brussels.
The document could provide new evidence about two of the new Commission team. Pascal Lamy, the new French commissioner-designate for trade, could be implicated because of his role as the chief aide to Jacques Delors, the Commission president who stood down in 1995. Erkki Liikanen is in the firing line because he is a survivor of the old Commission.
Meanwhile the Green German commissioner, Michaele Schreyer, will face German Christian Democrats' hostility because they believe her position should have gone to someone from their ranks.Reuse content