Bloc Quebecois MP Jean-Francois Fortin is leaving the party and will sit as an independent until the 2015 federal election.
Fortin said in a statement today the Bloc Quebecois he joined no longer exists.
The 40-year-old has represented Haute-Gaspesie-La Mitis-Matane-Matapedia since 2011.
Fortin says new Bloc Leader Mario Beaulieu has a one-dimensional, uncompromising approach that ends the credibility established by previous party leaders.
He says Beaulieu has radicalized the party and isn't looking to reunite sovereigntists. Fortin believes his constituents would be better served if he completed his mandate outside the party.
His departure leaves the party with just three members in Ottawa.
Fortin was one of four Bloc members elected to the Commons in 2011 and the only non-incumbent.
Political analyst Jean Lapierre says Fortin's resignation may be just the first of several in the months leading up to next year's federal election.
"They're all in a bit of panic," he says. "I wouldn't be surprised if others MPs follow and then try to save their seats by saying they'll be the party of the regions or something like that. I hear those noises."
But he doesn't think Beaulieu is going anywhere in the short term.
"I see him as being able to stay on because the caucus doesn't mean much now," he says. "And the fact that the won [the party leadership race] based on popular support within the party [suggests] there's no reason that he can't go on until the election. The people of Quebec will have the last say."