Nawaz Sharif has stepped down as Pakistan's prime minister after the country's Supreme Court unanimously disqualified him on grounds that he lied about his assets during a corruption investigation.

The ruling comes after months of hearings in a case that was prompted by the "Panama Papers" leaks.

No Pakistani prime minister has ever completed a full five-year term.

Most have seen their tenures cut short by the powerful military or by the Supreme Court. Others have been ousted by their own party, forced to resign or have been assassinated.

What happens now?

Although Sharif has been disqualified as prime minister, he remains the head of the Pakistan Muslim League-Nawaz (PML-N), the largest party in the National Assembly.

As such, Sharif will oversee the nomination of his successor who will then be rubber-stamped in a parliamentary vote, where his party and coalition partners command a 209-seat majority in the 342-seat house.

The opposition is also expected to field a candidate for the premiership, though the nominee has a slim chance of getting sufficient votes.

The vote is likely to happen within a matter of days, if not hours, of Sharif's disqualification.

Is there any precedent for this?

Yes, in 2012 then prime minister Yousaf Raza Gilani was disqualified over contempt of court charges for refusing to reopen a corruption case against the sitting president Asif Ali Zardari.

Could the court's decision be challenged?

In theory, yes, but it is highly unlikely.

Sharif's legal team could file a review petition but only on very limited grounds, such as a mistake in the judgment.

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"The Supreme Court is the interpreter and final arbiter of what the constitution means, so if the Supreme Court says that's how it's supposed to be done, then for all practical purposes that is what it is," said constitutional lawyer Yasser Latif Hamdani.

Could an early election be called?

An early election is unlikely because according to the constitution it can be called only by the president on the advice of the prime minister, meaning a successor to Sharif would have to be chosen first.

Elections are due in 2018.

Could the military take over (again)?

The military has been in charge of Pakistan for half of its 70-year history, but few expect the army to make an explicit bid for power again.

The military already exerts control over foreign policy and defence, leading to accusations from some that it is carrying out a "creeping coup".

"The military doesn't need to take over because it already enjoys so many trappings of power from behind the scenes," said Michael Kugelman, deputy director of the Asia Program at the Washington, DC-based Wilson Centre.

In addition, Kugelman points out, public opinion in Pakistan does not favour a return to martial law.

"There is also simply not as much of an appetite in Pakistan for military rule as there was in previous years. That's important for the military because the military is very concerned about its image and public opinion towards the army," Kugelman said.

Who could be Pakistan's next PM?

Shahbaz Sharif

Speculation within the vocal local media suggests that the party is planning to bring in an interim prime minister for a few weeks before electing Sharif's younger brother Shahbaz Sharif to the post.

The young Sharif is currently chief minister of the Punjab province, the Sharif family stronghold.

Khawaja Muhammad Asif

Defence Minister Khawaja Asif is one of the most trusted allies of the outgoing prime minister and considered the mostly likely to succeed him.

The former banker has held a series of key positions within the PML-N since 1991.

Sardar Ayaz Sadiq

The speaker of the National Assembly, Sardar Ayaz Sadiq is another strong candidate for next prime minister who is said to have the ear of the ruling Sharif family.

Sadiq gained Sharif's trust after he defeated the PML-N leader's main rival, cricketer-turned-politician Imran Khan, in a hotly contested race for a Lahore seat in the 2013 general election.

Ahsan Iqbal

A US-educated politician, Ahsan Iqbal hails from a political family that has long been associated with Sharif's PML-N party.

Iqbal is considered the development brains of the party and a visionary leader.

He currently heads the federal planning and development ministry, having previously served as minister for education and minorities.

Chaudhry Nisar Ali Khan

Interior Minister Chaudhry Nisar Ali Khan, a stalwart of the PML-N, was until recently considered the prime candidate to succeed Sharif.

But relations between the two have recently cooled, with some sources suggesting that Sharif is concerned that the vocal Nisar could be positioning himself to wrest control of the party from the embattled prime minister.