Yesterday, for the first time, Britain said that Robert Mugabe had no right to call himself the President of Zimbabwe and that the world should try to get him out. Strong words, although tailing off into euphemism about exactly how other countries should do that.

The weakness in this call for sanctions - which is not at this point, ministers made clear, a call to arms - is Zimbabwe’s nervous but immobile neighbours. The task is to persuade them, as they sit watching the rising tally of deaths, the hunger, the inflation of more than a million per cent, that even if humanity won’t prompt them to act, self-interest now should.

“This Government, this status quo, is not something we can accept or live with,” Lord Malloch-Brown, Foreign Minister for Africa, said. “We do not recognise the Mugabe Government as the legitimate representative of the people of Zimbabwe,” David Miliband, Foreign Secretary, later told the House of Commons.

Unambiguous, finally, and free of the fear of seeming like a colonial power, which has kept Britain too reticent for too long. The turning point, Lord Malloch-Brown said, was Sunday’s rally, where the opposition Movement for Democratic Change persuaded a judge to overturn a ban, only to find itself confronting thugs with clubs from the ruling Zanu (PF) party.

But now that Britain has said that it wants an end to the Mugabe regime, what can it actually do? Not much on its own, although Lord Malloch-Brown said it might now look at forcing the few British companies that still did business there to cut all ties. In answer to a question about whether Britain might strip Mugabe of his knighthood, he said drily, “I can’t imagine anyone in this room, including this minister, thinks he should keep it. But for the mangy old British lion to rise to its full height and say, this is outrageous, you’ve lost your knighthood . . .” - it would not, he concluded, match the gravity of the offence. “We don’t want it to be Zimbabwe versus Britain, it’s Zimbabwe versus the world,” he said.

What should the world do? More sanctions, and more targeting of those in the regime, including perhaps their foreign assets and children’s education. But not, he argued, blocking remittances or cutting off electricity, because these would hurt the poorest.

This makes sense. But it is vague about how this might dislodge a leader who has said he will consent to be removed only by God. The intention appears to be to prompt some within Zimbabwe to overthrow Mugabe. The risk is not just of a worse bloodbath, but that some of those most equipped to do that, including army generals, are not those who might rush to form the kind of “democratic government representative of all the people” that Britain wants. All that other countries can do is to offer lavish rewards to a new government that resembles that ideal.

A risky plan, then, but better at this point than military action (Miliband, with a stutter, brushed away a Commons question about whether Britain would send in the SAS). But a flurry of meetings this week will test whether there is any real support from other countries. “We are at one end of the spectrum,” Lord Malloch-Brown said, describing Britain’s efforts to urge a tougher stand. “But the spectrum is moving towards us.”

Slowly, though. The most important signal will come from the African Union (AU), egregiously indulgent so far, which has one of its regular meetings later this week. There were signs during the Zimbabwe election campaign, Lord Malloch-Brown said, of interest by some AU members in a role for international peacekeepers. For the AU, this would be a radical and welcome step forward. He also claimed to see signs that South Africa was moving in a tougher direction. We’ll see. If it were not for the world’s reverence for Nelson Mandela, now celebrating his 90th birthday, and its deep respect for South Africa’s own journey to democracy, there might have been much louder opposition to President Mbeki’s determined evasion of the Mugabe problem - comparable, say, to the criticism of China for support of the Sudanese Government.

The United Nations Security Council could be hugely important but is not yet close to the necessary pitch. Yesterday’s meeting was always going to consider Zimbabwe, but only to take stock of humanitarian help. Miliband warned the Commons about Britain’s struggles, unsuccessful so far, even to get Zimbabwe made a standing item on the agenda. The council, and the meeting of foreign ministers of the G8 later this week, will test China’s willingness - so far absent - to join a united front.

This might be a rare time where the EU moves first, although only because members have least at stake. Last week they signalled support for tougher measures, although they did not name them.

Britain is right that this conflict is between Zimbabwe and the world. It is to the world’s discredit - and South Africa’s, above all - that it has so far ducked the battle.

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