OTTAWA - The Bloc Quebecois is losing one of its most vocal pillars.

Michel Gauthier, the MP for Roberval-Lake-Saint-Jean, has announced his withdrawal from political life, effective the end of the current parliamentary session.

Gauthier says he won't run in another election campaign for health reasons.

The announcement of his departure comes just days after the Quebec sovereigntist movement was struck another blow when the Parti Quebecois was relegated to third-party status in the province.

Gauthier has occupied a prominent role within the Bloc Quebecois, often standing in for party leader Gilles Duceppe during question periods in the House of Commons.

He has also been a key player in preparing the Bloc's most recent election campaigns.