The Munster MEP, Mr Pat Cox, has dismissed suggestions that Ireland's rejection of the Nice Treaty could wreck his hopes of becoming President of the European Parliament next year.
The Spanish newspaper El Pais claimed this week that Spanish conservatives planned to vote against Mr Cox, partly because of the referendum result.
The report, which Mr Cox described as "mischevious", suggested that some Spanish MEPs believed that, as an Irishman, the Munster MEP might be soft on Basque terrorism.
"This is a degree of national character assassination that is deplorable," Mr Cox said.
Under a deal between the conservative European People's Party (EPP) and the Liberal group he leads, Mr Cox is expected to succeed Ms Nicole Fontaine, a French conservative, as president of the parliament next January. But if some conservatives refuse to support Mr Cox, the position could go to Mr David Martin, a popular Scottish Labour MEP who is the candidate of the Socialist group.
Mr Cox insisted yesterday that he had received assurances from the Spanish conservatives that they would vote for him and he said the EPP leadership was thoroughly committed to the deal they had agreed in 1999.
He acknowledged that Ireland's rejection of the Nice Treaty was a shock to our European partners but said that, if he failed to become president of the parliament it would not be because he was Irish.
"I don't believe so. I don't think that will be a factor," he said. Mr Cox is regarded as one of the most gifted speakers in European Parliament debates and has won admiration for his skilful leadership of the Liberal group.
He has formed a network of flexible alliances within the parliament and, although the Liberals occupy only 52 out of 626 seats, Mr Cox is one of the most influential power-brokers within the European institutions.
Even if the EPP keep their promise to vote for him, however, Mr Cox needs a further 30 votes to be elected.
He said yesterday that he would seek "everywhere" for those votes, implying that he hopes for support from some Socialist MEPs as well as from smaller groups in the parliament.
Like Mr Cox, Mr Martin is a popular, experienced figure who is admired by MEPs from all groups in the parliament and both men will start campaigning in earnest next month.
As a left-winger, Mr Martin could be attractive to the Greens but may have difficulty attracting conservatives.
Some British observers have suggested that Mr Tony Blair would prefer to see a moderate figure such as Mr Cox winning rather than a traditionalist like Mr Martin.