Analysis: No 10 hopes the 'Thatcher factor' can ease pressure

Before the war began, Tony Blair's advisers judged that many people who opposed it would respect him for not backing down and swing behind military action once the fighting started.

In private, Blairites mention a "Thatcher factor": although many people didn't like Margaret Thatcher, they respected her. Since his days as a new MP, when Baroness Thatcher was Prime Minister (with a majority of 144), Mr Blair has always been a little besotted with the Iron Lady.

"People like strong leadership even if they don't love the leader," said one aide.

The Blair camp also hoped that patriotic support for British forces would also ease the pressure on the Prime Minister once they were engaged. True to the predictions, the opinion polls have turned since the war started, and the numbers of people who approve and disapprove of it have changed round. The latest survey, by ICM, suggests that 54 per cent support a military attack on Iraq to remove Saddam Hussein, with 30 per cent against. In February, the figures were 52 per cent and 29 per cent respectively.

Labour's private polling suggests stronger support among working-class voters, who have swung behind "our boys", than the professional classes, who have not dropped their hostility to war or been won over by Mr Blair's undoubtedly persuasive skills. This ties in with the findings of MPs who reported before the war that opposition in middle-class constituencies was stronger than in working-class constituencies. The split helps to explain the rise in support for the Liberal Democrats, who are doing well among the AB1 socio-economic group.

But Mr Blair's advisers also know that public opinion is expecting a quick victory. This perception was clearly fuelled more by Washington than London, perhaps in the hope of persuading Iraqis to desert President Saddam.

The fear among ministers is that public opinion will prove fickle and that the "switchers" who reluctantly support the war at present could swing back to hostility as the conflict drags on. Public perception is all. Current levels of support for the war could easily be eroded by the daily reports of resistance in southern Iraq, accidents and tragedies. Despite Mr Blair's insistence that the military campaign is on track and the difficulties were foreseen, he could yet face a "wobble" in public support that could translate into a weakening of the broad political backing the war currently enjoys.

Despite the Cabinet's determination not to provide a "running commentary," Sky News, BBC News 24, ITV's News Channel and the American networks are giving us one anyway. So the Government is being forced to get its act together quickly.

Yesterday Mr Blair urged people not to consider only what they saw on television, saying that while it was real it was not the whole picture. Behind this appeal lay the recognition that images of suffering in the battle for Baghdad could swing the pendulum of public opinion back again.

Mr Blair still hopes he can help to mould a new world order from the ashes of the war and the failed diplomacy that preceded it. All his powers of persuasion will be needed to work on America and Europe if the deep divide between them is to be bridged. That process will start in his talks with President Bush at Camp David tonight and tomorrow and, if successful, could help Mr Blair to emerge from the war strengthened. For the time being, however, his fate is largely in the hands of military commanders in the desert.