The speech that Benazir Bhutto gave last night, 18 hours after twin blasts failed to kill her, was not the one that she had planned to make to celebrate her homecoming, but it was the most powerful of her career.

Dressed in slate grey, with heavy-rimmed glasses, her dark hair hanging loose down her back below her white scarf, she stood in the courtyard of her family home in Karachi, shielded by high walls, and spoke forcefully for an hour as the moon rose.

“Something in my heart told me it was not a firecracker,” she said of the first of two explosions that left 140 dead and hundreds injured. “Then we saw the huge orange light which lit up the ground, and we saw bodies spilling over. There was blood and gore on all of our clothes.”

Pakistan was in shock yesterday as the implications of the assassination attempt sank in. The military Government of President Musharraf has been unable to check the surge in terrorist attacks, gripped as it has been by the constitutional stand-off with the courts and two main political parties, which are pressing for an immediate return to democracy.

“This was a dastardly and cowardly action, the first in the history of Pakistan on a political leader,” said Ms Bhutto, 54, twice Prime Minister, who returned this week from eight years in voluntary exile to campaign for elections next year for her Pakistan People’s Party (PPP). “It is not an attack on one political leader, it is an attack on all leaders.”

Only a minute before the blasts she had stepped down from the rooftop platform of her bus into the fortified body of the vehicle “to loosen the straps on my shoes, as my feet were swollen”. She had been standing for most of ten hours as her bus crawled along the route from the airport through the million-strong crowds. Officials said yesterday that they had expected it to take another 48 hours to arrive at the tomb of Muhammad Ali Jinnah, the founder of Pakistan.

Police officers, stung by criticism that they should have protected her better, retorted that her convoy was impossible to protect once she decided to let it be engulfed by crowds of such size. Her party had been working for weeks to swell the numbers to a politically formidable level.

Ms Bhutto had taken the advice of her officials to go to the lower deck as it passed high-rise flats, she said, for fear of presenting an unmissable target. But although a bulletproof shield had been made for her protection when standing on the roof, “I did not stay behind it,” she said. “It would have been wrong of me when so many had come so far to see me.”

If her political secretary, sitting with her downstairs, had not suggested drafting a one-paragraph addition to the speech she planned to give at the tomb, she would have been back on the roof when the explosions happened.

Despite her narrow escape, the security checks to enter her house were almost absent yesterday. More than 200 reporters and party members crowded through the gates but women’s bags were not searched, and although the television cameras, laptops and power supplies sent the walk-through scanners beeping crazily, none was examined.

“They trust good faces,” said Akbar Khawaja, a former World Bank official and senator, whose term finished last year.

That enthusiastic chaos, which PPP supporters feel is its endearingly human quality and its critics feel should disqualify it from office, yesterday nearly destroyed the speech that will determine Ms Bhutto’s political future. Throngs of party workers had not thought to find a microphone, and she had to repeat the first sentence of her prepared speech six times because her voice was inaudible. On Thursday, on her arrival, the 150 loyalists who had travelled with her from Dubai even delayed her from leaving the plane for 25 minutes, defying the pilot’s instruction to sit down as they twirled and chanted in the aisles. In the end, she had to take the cabin address system herself to secure enough order for the aircraft to be allowed to taxi to the arrival gate.

Early signs were that the blasts would give Ms Bhutto a huge boost and consolidate her party’s position as the dominant force in Pakistani politics. As leader of the PPP, the left-wing party of the Pakistani political mainstream, she is the self-proclaimed “voice of the voiceless, weapon of the weak”. The courage and fatalism that she displayed yesterday in vowing to keep on campaigning have threaded through three decades of political life. She inherited the PPP leadership from her father, Zulfikar Ali Bhutto, who was deposed as Prime Minister by the military and executed in 1999.

“I didn’t choose this life; it chose me,” she states at the start of her autobiography, published last year.

The blasts will put huge pressure on President Musharraf, who is regarded widely as having lost control of rising violence despite being a military leader. Yesterday Karachi, a city of 14 million, swollen further by Bhutto supporters, was unrecognisable as a commercial and financial hub. Schools and shops were shuttered and its six-lane highways, normally immobilised by jams, were empty.

At the Jinnah Memorial Hospital, the largest in Karachi, bitter, shocked PPP supporters gathered in search of missing relatives. There were at least 26 bodies still lying on the floor and on trolleys, the dim, windowless corridors reeking of decomposition in a temperature of 40C (100F) as people tugged away the blood-soaked sheets. Four were no more than heads and shoulders; many were scorched, with eyelids, lips or toes burnt away. Many of the dead were police and PPP security guards; all were men except one woman and one girl.

Many of the survivors and the relatives in the hospital expressed intense anger against President Musharraf and his Government, blaming him either for actually planning the explosions or for failing to prevent them.

Among the injured, Muhammad Varis, a security guard for Ms Bhutto from Dadu, a town in her own Sindh province, lay unconscious next to his red, black and green PPP shirt and his security pass bearing the motto “We will lay down our lives for Benazir Bhutto”. His cousin, who said that 900 people had travelled together from his town, speculated that the bomb had been planted in a police car and blamed the Government.

Mazar Khan, his neighbour, who had been standing near the blast, said: “How come the Government kept warning of a suicide bomb? It knew.” None blamed al-Qaeda, despite recent threats from militants linked to the group that they planned to attack Ms Bhutto on her arrival.

“I don’t know who did it. It could be the ISI [the intelligence agency], or it could be al-Qaeda,” said one man from Mali, a village outside Karachi. “But it is the responsibility of Government to protect her and the crowds.” Another added: “It is the Government, not al-Qaeda. They wanted to stop Benazir Bhutto.”

That anger could be powerful fuel for a politician who had showed, before the blasts, that eight years in exile had not erased her appeal. But the attacks, which “turned the triumph of morning into the tragedy of evening”, as she put it, give a grim back-drop to her usual message of hope.

This week she made a resonant case for the return of democracy in Pakistan and the end of military rule. But she still has to convince a deeply alarmed country that she has the answer to the extremists.

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