Mariano Rajoy defend himself and the Popular Party against accusations of corruption on Wednesday morning, after being forced to appear in parliament by opposition groups.

The Prime Minister claimed he had made 52 statements on corruption over the years, and answered 32 questions related to fraud during Prime Minister's Questions sessions in the lower house.

"I have always appeared before this chamber […] that is my duty as Prime Minister."

"You have not told the truth about the funding of your party", Margarita Robles, spokeswoman for the Spanish Socialist Party (PSOE), retorted, adding that the PM should "resign out of dignity".

"Only someone who is incompetent could not know what was happening in his party", said Podemos leader Pablo Iglesias: "the conclusion is that you are lying".

"You don't deny the facts, you deny you knew anything about them."

Both left-wing parties charged that events and details surrounding the illegal funding of the Popular Party—including off-the-books accounts, untaxed income for senior leaders and backhanders from companies that were later awarded public contracts—from the late 1990s onwards are now established judicial fact.

The PSOE spokeswoman, Ms. Robles, happens also to be a judge.

Mr. Rajoy said that he did not "oppose political responsibility" being demanded of him in parliament, but that the correct means for doing so was not an extraordinary session but a motion of no confidence.

"This chamber has not withdrawn its confidence in me or, to put it another way, it has not held me responsible", he said: "My duty is to govern and I shall continue to do so".

The Prime Minister used his opening remarks to defend the anti-corruption measures introduced since the Popular Party returned to power in 2011, including a ban on corporate finance and another ban on banks pardoning political parties' debts.

Ms. Robles (PSOE) said the PM's "moral superiority" and "arrogance" made her blush: "To say that you are working for justice shows a lack of respect for justice professionals".

"At which precise moment did you find out the financing of the PP was illegal?", wondered Mr. Iglesias (Podemos): "I hope you won't reply that you read about it in the newspapers".

Albert Rivera, the leader of Ciudadanos, criticised Mr. Rajoy and the other parties for turning parliament into a political rally, before proceeding to praise his own party and announce their favoured measures against corruption.

"You have neither the legitimacy nor the will to fight against corruption", he said.

He announced Ciudadanos would introduce a bill in the autumn to limit the number of years a prime minister can serve.