This is a mirror image of the position before the war, when a similar YouGov poll showed 36% backing for military action and 57% opposed.

Support for the war is stronger among men than women, but is shared across all age groups. Labour and Conservative supporters back the war by two to one. Only Liberal Democrat supporters are opposed, in line with their party’s official position.

The war is also seen as being of benefit to the world. By 45% to 35%, people believe it will make the world a safer place.

The expectation is that the war itself will be short. More than two-thirds, 70%, say it will be a brief campaign, although 39% think there will be heavy casualties.

Tony Blair’s conduct of the crisis is gaining support, following initial public opposition. More than a third, 36%, say their admiration for the prime minister has increased because of the way he has handled the Iraq crisis in recent weeks, against 29% who say their respect has diminished.

Most of those surveyed, 59%, say they saw the prime minister’s address to the nation on Thursday evening, when he set out his reasons for going to war. By three to one, 27% to 8%, people said they were more convinced of the need for war by the broadcast, with the rest unmoved by it.

People are also unhappy about the wave of protests by schoolchildren in the past few days. Fewer than a quarter, 24%, believe pupils have a right to protest at any time. Nearly two-thirds, 63%, think teachers should have kept the children in school.

The political threat to Blair appears to be fading, with little enthusiasm for any of his potential successors in the cabinet. Gordon Brown tops the list, with 24% support in the event of Blair stepping down, followed by Robin Cook, 9%, Jack Straw, 7%, and David Blunkett, 6%. Most favoured none of the prime minister’s likely replacements as leader.

Blair is seen as more sincere than George Bush over rebuilding Iraq and pursuing the Israel-Palestine peace process. By 72% to 19%, people say he is sincere about reconstructing Iraq for its people, against 51% to 35% for the US president. On finding a solution to the Israel-Palestine problem, people say by 68% to 18% that Blair will push for peace, compared with 41% to 39% who think Bush will.

Asked whether Bush will pursue war against other countries such as North Korea after Iraq, most people think he will. By nearly two to one, 53% to 27%, they predict the US will target other nations believed to pose a threat.

YouGov surveyed a representative sample of 2,116 adults, online, on March 21-22

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