Any remaining doubts about Robert Mugabe's response to Zimbabwe's presidential election were demolished at the weekend. He intends to steal it. Gone are the hopes that he might retreat to his suburban mansion under cover of a guarantee of immunity from prosecution. The idea that he might heed a united call to step down at Saturday's emergency regional summit is, likewise, a memory. It is now painfully clear that Mr Mugabe intends to keep the presidency by force if necessary, and reverse his historic parliamentary defeat of March 29 into the bargain.

This is the significance of the 23 recounts demanded by Mr Mugabe's Zanu (PF) party and granted by the Zimbabwe electoral commission. Zanu (PF) needs only nine more seats to win back control of Parliament. Given the intimidation already unleashed by loyalist “war veterans” in key constituencies, the regime's desired result appears a foregone conclusion. But it would be a crime against the people of Zimbabwe. It would mark the worst failure to date of the policy of “quiet diplomacy” by which South Africa's President Thabo Mbeki has claimed for eight years to be reining in Mr Mugabe's de facto dictatorship. And it would make a mockery of Britain's longstanding support for this policy.

Western governments hoped the weekend summit in Lusaka would produce a regional solution to Zimbabwe's crisis. It did not. Mr Mugabe said he would attend, then decided not to. Mr Mbeki paid court to him instead, declaring afterwards, against the evidence of four million Zimbabwean refugees in his own country, that were was “no crisis”. The SADC summit closed with a statement that made no mention of Mr Mugabe but did include a surreal plea for the release of election results “in accordance with the due process of law” - in a country that tore up due process nearly ten years ago. In London yesterday, Downing Street welcomed that statement.

The Movement for Democratic Change has vowed to challenge the proposed recounts in court tomorrow, and has called a general strike for the same day. If the intimidation of the past two weeks is any guide, both initiatives appear doomed. But on Wednesday the spotlight will shift from Harare to New York, where Mr Mbeki and Gordon Brown will have a chance - perhaps their last - to pluck diplomatic victory from the jaws of humiliation. British efforts to lead effective action against Mr Mugabe at the UN have hitherto foundered on two obstacles: the non-cooperation of powerful members, notably China, out of narrow self-interest, and Mr Mugabe's skill in turning criticism by Zimbabwe's former colonial master to domestic advantage. But his rhetoric no longer wins elections, and as the Olympic torch stumbles round the world, China's overwhelming need is to burnish its image, not tarnish it further.

This is decision time for Mr Brown. Has “quiet diplomacy” worked? After eight years, the only positive item on the balance sheet is one tolerably fair election, and it is about to be stolen. At the UN Mr Brown should therefore heed his bolder advisers and, with Mr Mbeki, call for a resolution that would demand full publication of the election results and reserve the power to imposed targeted sanctions on Mr Mugabe's inner circle, who are clinging to power even more anxiously than their leader. They have brought their people purgatory, not liberation, and they have blood on their hands. If the UN fails to act, it will be complicit.