Pakistan’s political rivals pledged to contest next week’s highly charged election last night as Bilawal Zardari, the son of Benazir Bhutto, took over at the helm of her Pakistan People’s Party (PPP).

The decision ended the threat of a boycott of the elections, scheduled for January 8, in protest at Ms Bhutto’s assassination and amid calls for President Pervez Musharraf to stand down.

Pakistan’s Electoral Commission is due to meet today to consider whether to postpone the election for several weeks in the hope that the violence that has swept across the country will abate, allowing election campaigning to resume.

Rioters have ransacked banks and petrol stations, brought the rail network to a halt and smashed hundreds of cars and shops. They have also wrecked nine election offices, along with the voter rolls and ballot boxes inside, hampering the printing of ballot slips and the training of poll workers, the election commission said.

In fresh violence yesterday, two men blew themselves up close to the residence in eastern Pakistan of Ijazul Haq, the former Religious Affairs Minister and senior leader of the ruling Pakistan Muslim League-Q party. Both men died, but there were no other casualties.

“Despite this dangerous situation, we will go for elections, according to her will and thinking,” said Asif Ali Zardari, Ms Bhutto’s widower.

Nawaz Sharif, the opposition leader who was Ms Bhutto’s bitter rival, indicated that his Pakistan Muslim League would reverse a decision to boycott the election. “It is likely that the party will take part,” said Ahsan Iqbal, a spokesman for the Pakistan Muslim League. “If they [PPP] don’t mind contesting elections after Benazir Bhutto’s assassination, then there is no point in our boycotting general elections,” he said.

The identity of Mr Sharif’s main opponent from the PPP has not yet been confirmed, although there is speculation he will stand against Makhdoom Amin Fahim, a PPP vice-chairman, in the contest for Prime Minister.

In her will, Benazir Bhutto had nominated her husband, Asif Ali Zardari, as her successor, but he passed on the mantle to his son, Bilawal, aged 19.

Mr Zardari, a former minister in his wife’s Government, said that he would run the party until Bilawal completed his studies at Oxford. However, he has not put himself forward as a candidate, possibly fearing public recriminations against his nomination. Mr Zardari has faced allegations of fraud and was only able to return to Pakistan with his wife after charges against them were dropped as part of a deal with Mr Musharraf. He had spent more than seven years in jail on corruption charges before being freed on bail in 2004 and had lived in New York and Dubai since then. He returned to Pakistan on Friday for the funeral of his wife.

Mr Zardari, who had earlier spent two years in jail in the mid1990s, is still facing charges at a Swiss court of money laundering. He is accused of siphoning off $1.5 billion (£750 million). However, Mr Zardari has emerged as one of the most powerful figures in the country as Pakistan passes through the most critical situation in its recent history. Yesterday he rejected a government explanation that his wife was killed when the force of the suicide bomb smashed her head into a lever on the sunroof as she ducked down when shots were fired.

Her party says she was shotdead and Mr Zardari said he wanted the United Nations to investigate along the lines of the commission that investigated the killing of Rafik Hariri, the former Lebanese Prime Minister.

Channel 4 television last night broadcast previously unseen footage of the assassination, showing a man firing a gun, quickly followed by an explosion. She was seen falling into her car after the shots were fired.

Gordon Brown spoke to Mr Musharraf about help for an investigation into the assassination, Downing Street said. The Prime Minister also urged him to avoid any “significant delay” in holding elections. The two leaders spoke as Mr Zardari made his call for international assistance in the investigation.

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