Pakistan’s embattled president, Pervez Musharraf, came under mounting pressure to quit this weekend amid speculation he was already in talks over a deal for his resignation.

A spokesman for the Pakistan People’s party (PPP), which leads the ruling coalition in parliament, warned that the former dictator would face impeachment if he did not go.

The ultimatum was issued after suggestions that Musharraf was negotiating terms under which, if he agreed to go quietly, he would be granted immunity from prosecution for overthrowing the government of Nawaz Sharif in 1999.

He denied the claims that he was close to departure, calling them a “malicious campaign”.

Parliamentary support for Musharraf, who was elected to another five-year term last November, collapsed after February’s general election in which the parties that backed him were virtually wiped out. Last week he held late-night meetings with his successor as chief of the army staff, General Ashfaq Kayani.

In a further development, a Musharraf loyalist was removed from the command of the army’s Triple One Brigade, known as the “coup brigade”, for its role in several of the country’s military takeovers. The move was widely seen as a ploy to prevent Musharraf from dismissing the government.

Pressure has mounted on Musharraf since Asif Zardari, widower of the PPP’s assassinated leader Benazir Bhutto and the party’s co-chairman, denounced him as a “relic of the past”, standing between the people and democracy. “He [Musharraf] has taken off his uniform . . . but that doesn’t make him into a democrat or a civilian president,” he said.

Tension mounted when Sharif, the PPP’s junior coalition partner, denounced the president as a “traitor” and said he should be charged with “high treason”. He said that he had told Zardari that Musharraf should be sacked without a “safe passage” deal, and that the PPP leader had agreed.

In a televised speech last week, Zardari declined to offer Musharraf any support but said he was committed to “dialogue, patience and dignity”.

The favourite candidate to succeed Musharraf is Makhdoom Amin Fahim, a long-standing PPP loyalist.

Last night Lieutenant-General Talat Masood, an influential retired general, said a move against Musharraf appeared imminent. “Things have to change, and it’s only a matter of time,” he said.

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