Gordon Brown today sought to ratchet up the pressure on Robert Mugabe - calling on the international community to tell the Zimbabwean president that "enough is enough".
With the beleaguered African state now in the grip of a cholera epidemic which has claimed hundreds of lives, the Prime Minister said the situation had deteriorated to the point where it demanded an international response.
"This is now an international rather than a national emergency," he said in a statement.
"International because disease crosses borders. International because the systems of government in Zimbabwe are now broken. There is no state capable or willing of protecting its people.
"International because - not least in the week of the 60th anniversary of the universal declaration of human rights - we must stand together to defend human rights and democracy, to say firmly to Mugabe that enough is enough."
His comments echoed US Secretary of State Condoleezza Rice who said on Friday that it was "well past time" for the president to leave office and suggested the international community should "push Mr Mugabe out".
South African Nobel Peace Prize laureate Archbishop Desmond Tutu also said, in an interview with Dutch TV, that Mr Mugabe must stand down or be removed "by force".
But while Kenyan Prime Minister Raila Odinga has said it was time for African governments to "take decisive action to push him out of power", there has been little sign that Zimbabwe's immediate neighbours are prepared to move against him.
Mr Brown said he had been in close contact with African leaders to press for stronger action "to give the Zimbabwean people the government they deserve".
He said he now wanted to see an urgent meeting of the United Nations Security Council in New York to consider the worsening crisis.
In the meantime, the immediate priority was to prevent more deaths through the distribution of re-hydration and testing packs.
The Prime Minister called for the establishment of a "command and control structure" in the capital, Harare, to co-ordinate the work of donors and NGOs to ensure that international aid reached the people who needed it most.
Liberal Democrat leader Nick Clegg said the UN should now declare that the use of military force by the international community was justified in order to protect the people of Zimbabwe.
"The world has sat idly by whilst Robert Mugabe has brutalised his own people for too long. Economic recession in the West has led the world to avert its gaze from the suffering in Zimbabwe.
"The UN must urgently declare that Mugabe will be indicted in the International Criminal Court. The new doctrine of 'responsibility to protect' should be activated to justify outside force where that is possible.
"Further international inaction would be inexcusable."
He said that China must stop blocking international action through its veto on the Security Council, while South Africa had to abandon the "softly, softly" diplomacy of outgoing President Thabo Mbeki and take a tougher line with its neighbour.Reuse content