The attack was not immediately claimed, but it was swiftly condemned as the work of the IRA by the British and Irish prime ministers, who swore that the drive to bring peace to the province would not be halted.
The bomb exploded just after 11.20am close to both the Arndale shopping centre and Marks and Spencers. It sent a "white shower" of glass over terrified shoppers as they fled the scene. Police had been clearing the area, where an estimated 75,000 people had been shopping or at work, after telephone warnings that included a codeword.
They had identified the suspect vehicle, a Ford van bearing the words "Jack Roberts Transport" which, it was revealed last night, had been given a parking ticket just two hours earlier. Bomb squad officers, using a remote-control device, were examining it when it went off. One officer was seen running from the scene seconds before the explosion.
Thousands of shoppers were left shaken and shocked and up to 200 were injured, mostly by flying glass. By last night all but 15, one a pregnant woman, had been discharged from hospital. Dr Kevin Mackway-Jones, emergency consultant at Manchester Royal Infirmary, said: "The pregnant woman was thrown through the air for some distance and she has some abdominal pain. She is heavily pregnant but the baby's heart is still beating." It is believed the baby is due in eight days.
A number of the other casualties were believed to be German and Russian football fans in Manchester for today's Euro 96 match.
News of the bomb was brought to John Major as he attended Trooping the Colour in London on the Queen's official birthday. It came just five days after the opening of the peace talks in Belfast, from which Sinn Fein is excluded because there is no IRA ceasefire.
Mr Major described the attack as a "dreadful act", demanded a ceasefire and called on Sinn Fein to condemn the action. He added: "If the IRA think they can shift the resolve of any government with this action, they are cruelly mistaken." He was backed by Tony Blair, the Labour leader, and Paddy Ashdown, leader of the Liberal Democrats.
Gerry Adams, Sinn Fein's president, declined to condemn the attack unequivocally, telling a news conference: "If this explosion ... is linked to the conflict here in Ireland, obviously I regret [it] and I sympathise with those who have been injured." Asked if he would repudiate the bombing if it was the work of the IRA, he replied: "Let's wait until we have some clarity about all of this."
The return of violence was a bitter blow to the British Government, which had been leaning over backwards to make the talks process as acceptable to nationalists as possible.
John Bruton, the Irish Prime Minister, said: "Brutal, murderous acts of this kind are appalling and cannot be excused or explained away. Sinn Fein continues to associate itself with the IRA, allowing themselves to be used as accomplices in the IRA's cynical news-management strategy, providing political cover when that is needed for IRA actions and credulous acceptance of any IRA statement, no matter how contradictory."
The force of the blast was so great that the gable end of the nearby Arndale shopping centre was totally destroyed. Windows were shattered up to half a mile away and several small fires broke out. The explosion was heard up to seven miles away.
Chief Constable Malcolm Cairns, of Greater Manchester police, said last night that many lives had been saved by the successful evacuation. "It was a beautiful June day with tens of thousands of people in the city centre," he said. "Within the hour we had got everyone out of the line of sight of the bomb, and we went further than the usual guidelines."
Further reports, page 3
At the talks, page 7