Europe's powerful centre-right party met in Helsinki today to nominate its lead candidate for next year's European elections, in which populists and the Greens are expected to make gains.

More than 700 delegates of the European People's Party (EPP), the party of German Chancellor Angela Merkel, vote tomorrow in a process that will involve a fair amount of backroom dealing.

The two candidates in the running are Germany's Manfred Weber, a little known and low-key senior MEP, and former Finnish prime minister and Twitter-maven Alexander Stubb.

The winner of the secret ballot will be a contender to succeed Jean-Claude Juncker as head of the European Commission, a key prize in the top jobs horse-trading that will follow the EU elections next May.

Also in the mix are plum spots to lead the European Council - which represents national governments - the European Parliament, the ECB central bank or become the EU's foreign policy supremo.

Barring an upset, Mr Weber should win. The 46-year-old is head of the EPP group in the European Parliament and member of the CSU, the Bavarian sister party of Merkel's CDU.

Little known in Germany, Mr Weber is a great connoisseur of EU institutions and has received the key nods of Ms Merkel and the head of France's centre-right Republicans party, Laurent Wauquiez.

Mr Weber can also count on Austria's right-wing Chancellor Sebastian Kurz and Hungary's nationalist premier Viktor Orban to rally to his cause.

As an outsider, media-friendly Stubb has become the candidate of those who think the EPP should reject Orban's Fidesz and its increasing anti-EU rhetoric and authoritarian tactics.

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Mr Orban's place in the EPP was due to be one of the topics at a debate this evening between Mr Weber and Mr Stubb. But, for the time being, the expulsion of Mr Orban and his followers is not on the table.

"As I have often said, in every family there is an 'enfant terrible' (problem child). But I prefer to keep mine in the family and reason with him," said EPP chief Joseph Daul.