MADRID (Reuters) - Spanish anti-austerity party Podemos filed a motion of no confidence against Prime Minister Mariano Rajoy on Friday, citing a slew of corruption scandals that have shaken the ruling People’s Party (PP) over the last few years.

Podemos, which took around a fifth of the vote in last year’s two elections, does not have the numbers to pass the motion by themselves. However, the motion has been raised just two days before the Socialists chose their own leader after months without a head.

The motion will be voted on some time after next Thursday, although the Socialists are not seen toppling the government at this time.

On Sunday, however, the traditional left-wing opposition to Rajoy’s conservative PP choose between Pedro Sanchez, closest to Podemos in his firm stance against the PM, and Andalusian Susana Diaz, a moderate who helped clear the path for Rajoy’s win in October.

The third candidate in the leadership race is former parliament speaker Patxi Lopez, one of Sanchez’s chief allies during his time as leader, though he trails in the polls behind Sanchez and Diaz.

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The timing of the confidence motion is a direct challenge to the Socialists, hovering in the polls in close second behind the PP, alongside Podemos: pick a leader who may help dethrone Rajoy or one who will allow the left to languish in second place.

The battle for the left in Spain mirrors similar identity crisis amongst Socialist parties across Europe which have seen popular support dissolve from Britain to France to Germany as voters split along nationalist/globalist lines rather than traditional left and right.

Podemos, which has its roots in widespread protests during Spain’s economic crisis, said the motion was a rally against the PP’s use to public coffers and institutions to defend their own interests at the detriment to the electorate.

“There is a serious alternative to the PP. An alternative that respects human rights and democracy, that does not tolerate authoritarian practices, the plundering of public or corrupt practices,” spokeswoman for Podemos Irene Montero said on the steps of Parliament after filing the motion.

Dozens of PP members - including former economy minister and IMF chief Rodrigo Rato - have been implicated in graft cases over the last few years and months showing, say opposition parties, an entrenched level of corruption in the ruling party.