What started as a throw-away comment on a Finnish talk show has turned into a political funding scandal and left a smear on the Nordic country that cherishes its reputation as one of the world's cleanest, open and most transparent societies.

Timo Kalli, chairman of the Centre party, which dominates Finland's four-party, right-leaning coalition government, casually revealed he knowingly broke the law after failing to reveal who had made donations to his election campaign in 2007.