MADRID (Reuters) - Spain’s High Court found on Monday that the new leader of the opposition Popular Party Pablo Casado gained an academic degree in dubious circumstances, raising pressure on him as support for the conservative PP falls in opinion polls.

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Casado, who took over the former ruling party last month, denied any wrongdoing and said he was unaware of any irregularities in the awarding of his master’s degree nine years ago, adding that he had no plans to step down over the case.

The court said it could not hear the case due to immunity laws for members of parliament. However, it passed the case to the Supreme Court which must decide whether to proceed. Spain’s top court holds final authority in interpreting the immunity laws.

In its findings, the lower court said there were signs of bribery in the awarding of degrees to a number of people including Casado. “The director of the course ... acted so that a particular, chosen group of students were given a master’s degree (...) without any academic merit, giving it to them as a gift,” the ruling said.

Casado, who replaced former prime minister Mariano Rajoy as PP chief, rejected this finding. “Under no circumstances have I accepted a gift or requested something that was not given to any other students,” he told a news conference.

The masters degree was awarded to Casado in 2009 by Rey Juan Carlos University in Madrid.

The case is the latest to rock the PP, which led Spain from 2011 until June 1 this year when Rajoy’s government lost a parliamentary no-confidence vote. This followed the prosecution of dozens of people linked to the PP in a corruption case. Socialist leader Pedro Sanchez now heads a minority government.

Casado, has taken the PP to the right since becoming leader on July 21, faces an uphill struggle to regain voters.

According to a poll published last week, the Socialists now lead with 29.9 percent. The PP has fallen into joint second place with the market-friendly Ciudadanos party with 20.4 percent, according to the poll by the Sociological Research Centre.

In April, the head of the Madrid region Cristina Cifuentes, also a PP member, resigned after claims she had falsified her masters degree.