All the ingredients for a public health catastrophe were moving into place in Burma yesterday. The coconuts that many of the survivors have lived on since the cyclone struck nine days ago were running out, as was the diesel that powered the few rescue boats. Floodwater full of the bloated bodies of people and animals threatens an outbreak of cholera among people whose resistance to disease is dangerously weakened by exposure and lack of food and drinking water. Everywhere, stagnant pools are perfect breeding grounds for mosquitoes, threatening outbreaks of malaria and dengue fever. Most of the eastern Irrawaddy delta, hard to reach at the best of times, remains submerged and tropical storms are forecast for tomorrow.

Yesterday, Oxfam warned that without urgent action, the disaster could claim 1,500,000 lives and British Foreign Secretary David Miliband warned: "A national disaster is turning into a humanitarian catastrophe of genuine epic proportions, in significant part because of what I would describe as the malign neglect of the regime." The Boxing Day tsunami claimed 250,000 lives but few survivors died of disease thanks to an unparalleled international relief effort. History will remember the Burmese junta as the government that pressed ahead with a referendum designed to cement its hold on power and refused outside help, while hundreds of thousands of its people were dying needlessly.

There has been talk of international intervention with or without the junta's permission, under the terms of the UN's "responsibility to protect". But the Iraq war has done little to enhance the standing of humanitarian interventionism and predictably China and Russia led the objections. A half-way house would be dropping supplies by air, but this is a risky and inefficient way of delivering aid.

There are always excuses for inaction. In extremis, Britain should be prepared to join a coalition of the willing to defy the junta and save lives but the measure of any decision must be its effectiveness. It remains the case that the most efficient way of getting help to where it is needed would be with the co-operation of the Burmese government, which must be persuaded to listen before it is too late.