In the spotlight: Donald Tusk

These last few weeks were particularly shaky for the Platform, as one of the party's most recognizable figures, the former Mayor of Warsaw Paweł Piskorski, was kicked out of the party along with his closest supporters following accusations of unclear financial transactions.

The party has come a long way since Tusk became its leader in 2003. From a party that got 12 percent of the vote in the 2001 elections, and was considered an elite faction of businesspeople, he made it the largest opposition party in Poland, which has been beating the ruling Law and Justice (PiS) in the latest opinion polls.

On the other hand, there is also a fly in the ointment in Tusk's spell as PO leader. The party led in the opinion polls for the parliamentary elections and Tusk himself was favored to beat Lech Kaczyński in the presidential race. Yet both the party and its leader disappointingly lost the races in the last few meters.

Tusk, a member of the Kashubian ethnic minority, is a veteran of independent student movements in the late 1970s in Gdańsk. He was active in the Solidarity movement and in the 1990s he was one of the leaders of the Freedom Union (UW), which he left to establish PO. He is a big football fan and for years played on the Polish parliament's team.