PARIS, Dec 9 (Reuters) - French left-wing presidential hopefuls on Thursday rejected Socialist Party candidate Anne Hidalgo"s call to unite behind a single challenger, an outcome that leaves the left fragmented and scant chance of winning the April election. Hidalgo, who is also Paris mayor, warned a day earlier that if the left did not unite, it would "find it impossible to continue to exist in our country". read more Rivals said she was trying to revive a flagging campaign and dismissed her proposal for a primary to pick a left-wing candidate. "Anne Hidalgo has taken note of the dead-end her candidacy has hit, of the difficulty she faces in getting her ideas through...and wants to break the deadlock with a surprise," Green party candidate Yannick Jadot said, rejecting the idea. Hidalgo is polling at about 5% in voter surveys, behind Jadot and leftist firebrand Jean-Luc Melenchon who are both in the high single-digit percent. Communist challenger Fabien Roussel also dismissed Hidalgo"s proposal, as did Melenchon"s close political allies. The poor performance of leftist challengers in the polls reflects France"s lurch to the right in recent years. Polls show the front-runner in the race to be President Emmanuel Macron, a centrist whose social policies have drifted to the right as he courts conservative voters at a time immigration, security, national identity and job insecurity occupy the minds of voters. Two far-right candidates have the combined support of 35% of voter support and the conservative Les Republicains party"s pick, Valerie Pecresse, has seen a sharp bounce in popularity after her nomination last weekend. Those four occupy the top four places in polls. Only two candidates go through to the run-off vote.