The Supreme Court is hearing the PTI and PML-Q's joint petition against Deputy Speaker Dost Mazari's ruling in the Punjab chief minister's election.

A three-member bench — headed by Chief Justice Umar Ata Bandial, and comprising Justice Ijaz Ul Ahsan and Justice Munib Akhtar — is holding the hearing at the Supreme Court's Lahore registry.

The deputy speaker has been summoned by the court at 2pm. "We wish to personally hear from the deputy speaker," Justice Bandial said.

In addition, the top court has sent notices to Chief Minister Punjab Hamza Shahbaz, the Punjab chief secretary and the advocate general for Punjab.

The deputy speaker rejected 10 votes of the PML-Q, citing the apex court's opinion in the presidential reference for the interpretation of Article 63A, dealing a major blow to Pervez Elahi and paving the way for Hamza Shahbaz to retain the chief minister's slot.

Opposition (PTI and PML-Q) candidate Elahi managed to receive 186 votes, but after the deputy speaker's ruling, the PML-Q leader got only 176 votes, whereas Hamza received 179 votes.

The petition was filed late last night after the Opposition — which was confident of a victory — suffered the setback and vowed to challenge the ruling.

The Supreme Court of Pakistan, back in May, had ruled that the votes of dissident members of the Parliament (MPs), cast against their parliamentary party's directives, cannot be counted.

The apex court, issuing its verdict on the presidential reference seeking the interpretation of Article 63(A) of the Constitution related to defecting lawmakers of the PTI, said that the law cannot be interpreted in isolation.

During yesterday's ruling, Article 63(A) was applied after PML-Q President Chaudhry Shujaat Hussain wrote a letter to the deputy speaker, saying that he had directed the party to vote for Hamza Shahbaz.

The ruling has invited criticism from legal wizards as several believe that Mazari's decision was not in line with the Supreme Court's order.