However, it is unclear whether the men in uniform, who have staged multiple coups in Pakistan’s turbulent history, will stand aside while a former army chief is humiliated and dragged out of office.

Sharif said today that he was confident that “this is not the Pakistan of the 80s and 90s”. Zardari said that it was the wish of his late wife, Benazir Bhutto, who was assassinated in December last year, that her death would become “a catalyst of change”.

Sharif’s current politics are based on two themes: removing Musharraf and restoring to office the judges he sacked in November. However, many remain sceptical about Zardari’s sincerity about either of those causes.

In March Zardari made another dramatic announcement, also sitting alongside Sharif, that he would reinstate the judiciary. After four months in government, those judges remain out of office, and the PPP has come up with a series of reasons why it could not happen yet. However, impeachment is a far more complicated and risky manoeuvre than bringing the judges back.

The PPP came to power after months of careful secret negotiations with Musharraf and many believe that it continues to work on the basis of a “deal” that it forged with him. Under that arrangement, dozens of criminal charges against Zardari and Bhutto were dropped.

“Asif [Zardari] and Pervez Musharraf are inseparable, for their own self-interest,” said Iqbal Haider, a former law minister under Bhutto’s government of the 1990s. “Impeachment is a device to distract attention from the restoration of the judges.”

In the past, Musharraf has enjoyed strong support from Washington, as a major ally in the “war on terror”, which has given Pakistan billions of dollars in military aid. But it is now widely thought that he can no longer rely on the White House to bail him out.