Queen Elizabeth said she was "shocked" by the "appalling crime" in Omagh, Co Tyrone. In a statement within hours of the tragedy, she said: "Please pass my heartfelt sympathy to the bereaved, injured and those others who have suffered."
The Duchess of Kent also sent her "loving sympathy" to the bereaved and injured. In a message to the RUC Chief Constable, Mr Ronnie Flanagan, she said her prayers and thoughts were with the victims of the bombing and she praised the "courage and efficiency" of the RUC in dealing with the tragedy.
Before breaking off his holiday in Miradoux, south west France, to travel to Northern Ireland yesterday, the British Prime Minister, Mr Tony Blair, spoke with obvious emotion as he condemned the bombing as a "blast of evil" carried out by a "fanatical" group of people. Insisting that this "appalling act of savagery" would not be allowed wreck the future of the peace process, he said the bombers would be pursued "to the utmost" to bring them to justice.
"We will not let these people wreck the future . . . it does not belong to the criminals and the psychopaths," he added.
Speaking of his thoughts about the people who had been murdered, Mr Blair said: "Yesterday this time, this was just another normal day for them leading normal lives with the normal balance of cares and worries and hopes - and now by this blast of evil their lives are gone."
He said he grieved for those who would not see their parents or children again, but "we must be determined and we must say that these people who have perpetrated this deed will not win. They are not going to succeed. "They are a small group of people, a tiny fanatical group of people. They have no political base, they have no vote, they have no support in Northern Ireland. They have just this capacity for evil."
Ahead of his visit to the scene of the bombing, the Deputy Prime Minister, Mr John Prescott, also condemned the atrocity as a "barbaric act". Speaking on BBC's Breakfast with Frost programme, he said the British government would not be diverted from its objective of achieving peace in Northern Ireland and "we must all redouble our efforts" to achieve the goals set out under the terms of the Belfast Agreement.
The Home Office Minister, Ms Kate Hoey, who is from Northern Ireland, observed that the majority of people still wanted the peace process to work and joined Mr Blair and Mr Prescott in pledging not to rest until the perpetrators of the bombing served their time in prison.
The Conservative leader, Mr William Hague, offered his sympathy to the families of the dead and injured and insisted his party would stand "full square" behind the British government and the security forces in their search for those responsible. He described the bombing as an act of "unspeakable barbarity" that was designed purely to murder and injure innocent people. His condemnation was echoed by the Shadow Northern Ireland secretary, Mr Andrew Mackay, who said he hoped the Northern Ireland Secretary, Dr Mo Mowlam, would take the "dreadful events" in Omagh into account when considering the accelerated release of paramilitary prisoners. However, Mr Mackay fell short of supporting the call for a moratorium on prisoner releases, which was made by his deputy, Mr Malcolm Moss, on Saturday. Mr Moss had called for the change in policy until the bombers were identified and the full facts of the atrocity were known.
Instead, Mr Mackay called on the Sinn Fein president, Mr Gerry Adams, and chief negotiator, Mr Martin McGuinness, to use their influence to help the security forces identify the bombers. "You, and probably you alone, can ensure that these men are brought to justice very quickly. Take that opportunity and follow your good words . . . with equally strong actions," he said on Sky News.
The Liberal Democrat leader, Mr Paddy Ashdown, said he felt it was vital for all those who died on Saturday and for the victims of other atrocities in the North that the bombers did not succeed "in plunging Northern Ireland back into the blood". However, Lord Tebbitt, who was severely injured when the IRA bombed the Conservative conference in Brighton, struck a despondent note saying the bombing of Omagh had not surprised him: "This is what was predicted and what should be expected. The policy of successive governments has been to appease terrorism, to reward those who practice terrorism with political concessions and then to give them an easy ride out of jail."
The former Tory prime minister, Mr John Major, urged other terrorist groups not to retaliate and he called on republican and unionists alike to "work together" to ensure the bombers were caught speedily and punished. On the possibility of reintroducing internment, the Minister of State for Foreign Affairs, Ms Liz O'Donnell, said the Government was "not excluding anything at this point". In an interview with BBC Radio 4, Ms O'Donnell said Ministers would be making "very, very difficult decisions" about security over the next few days. "We are checking and examining our current legislation to see whether it is fit for the purpose in the new context of this threat to the State." Meanwhile, as the security operation swung into full force yesterday, the RUC Chief Constable, Mr Ronnie Flanagan, announced that a special task force had been established to investigate the bombing. The task force, which will be headed by the acting deputy assistant chief constable, Mr Eric Anderson, will be given additional uniformed and investigative resources. Mr Flanagan told BBC's Breakfast with Frost programme: "No stone will be left unturned until we bring these people to justice", he said.
Confirming that the investigation would concentrate on the dissident republican group, the Real IRA, Mr Flanagan, described them as "people who were out to murder people for the sake of murdering people".
Mr Colin Parry, whose son, Tim, was killed in the bombing of Warrington, described his "disbelief" at the events in Omagh. He told GMTV that at a time of such hope and optimism in Northern Ireland there were now hundreds more people who would go through "an awful, awful process but in time they will get some peace".