Leader of the Opposition in the National Assembly Khursheed Shah on Wednesday said that the decision taken by PML-N to put forward Shahbaz Sharif as prime ministerial candidate for the 2018 elections was a political one.

The decision had been taken after the top leadership of the ruling party converged on London a day earlier for a meeting chaired by former prime minister Nawaz Sharif, who is expected to return to Pakistan tomorrow to appear before an accountability court on Friday.

Prime Minister Shahid Khaqan Abbasi, Punjab Chief Minister Shahbaz Sharif and federal ministers Ishaq Dar, Khawaja Asif and Ahsan Iqbal had attended the London huddle.

Speaking to the media at the Parliament House, Shah said that he was happy that the former premier had decided to return to Pakistan to face the situation here.

"Jail and bail are common in politics," Shah quipped.

The former premier and his family are currently facing trial as accountability courts conduct hearings on corruption references filed against him.

Nawaz had remained absent from the previous hearing of the case as he had flown to London, where his wife is undergoing treatment for cancer.

Shah also criticised Pakistan Tehreek-i-Insaf (PTI) Chairman Imran Khan for not attending National Assembly sessions.

"If one wants to be involved in politics, then attendance in the parliament is necessary," he chided.

Shah said that all political parties will have to gather to discuss problems being faced by the country. He added that efforts are underway to ensure that the next general elections are carried out in 2018.

The leader of the opposition further said that Pakistan's relations with America will have to be brought under discussion.

"We will have to talk about statements made by Foreign Minister Khawaja Asif in Washington and the statements made by US Secretary of State Rex Tillerson in India," Shah said.

During a visit to India last month, Tillerson had said that the United States was concerned that extremist groups "left unchecked in Pakistan" posed a "threat to the stability and security” of the government in Islamabad.

Relations between Islamabad and Washington had become tense after US President Donald Trump announced his South Asia policy in August. As it called for greater Indian involvement in Afghanistan, the policy drew strong criticism from Islamabad.

During his policy announcement, Trump had also lambasted Pakistan for offering safe havens to "agents of chaos" ─ an allegation denied by Pakistan. Trump had also called on Pakistan to do more to eradicate safe havens on its soil ─ a stance maintained by Tillerson during his trip to Islamabad in October.