The showdown between seven candidates has no clear frontrunner and is expected to last several rounds during which candidates will try to broker deals with parliamentary groups to get the necessary support.

The election is not without drama amid a spat between parliament's two largest political groups: the right-leaning European People's Party (EPP) and the social-democratic Progressive Alliance of Socialists and Democrats (S&D).

According to a document published last week by the EPP, the centre-right group agreed in 2014 to support the election of S&D's Schulz in return for having an EPP candidate elected the following term.The S&D are now arguing against the election of a centre-right candidate, saying it would put conservatives in charge of all major EU institutions: the commission, the council and the parliament.

The EPP, the largest parliamentary group, wants to see its candidate, Antonio Tajani of Italy, elected, while the social-democrats are pulling for their own Italian, S&D leader Gianni Pittella.In the first three rounds of voting, a candidate needs a simple majority among the 751 members of parliament. Neither party has a big enough membership to elect its candidate this way, which is where the deal-making comes into play.

The election is expected to go into a fourth round, with victory going to the candidate who receives the most votes.