How many Iraqis will die today? Maybe 10. Maybe 100. We have no way of knowing. Blair and Bush, who invaded and occupied Iraq in order to make the world a safer place , say there is no reliable way to count Iraqi casualties - and so they will not try. Thus they refuse to accord innocent Iraqis the same status as our own dead and injured, whose names we rightly record and honour.

In an open letter to the prime minister on Wednesday, 46 diplomats, academics, health experts and religious leaders called on him to commission an independent inquiry to count the casualties in Iraq.

Blair responded by telling the House of Commons that the Iraqi health ministry has done the "most accurate survey that there is". But these figures - 3,853 dead and 15,517 injured - are not a survey, they are a partial count covering a six-month period from April to October this year. Even Iraqi officials acknowledge it to be an undercount.

Iraq Body Count's ongoing tally of recorded civilian deaths is based on official Iraqi figures, media reports and information from aid organisations. It does not pretend to be a complete count, but stands at between 14,619 and 16,804 deaths.

In October, the Lancet published the results of on-the-ground surveys which estimated the number of civilian deaths since invasion at a much higher figure of around 100,000.

The study also reported that the risk of death by violence is vastly higher now than it was before the war. The authors of the study, prominent scholars from the US and Iraq, describe their figures as estimates, but they are based on peer-reviewed scientific methods.

Research by the health charity Medact concludes there has been a substantial deterioration in the health of the Iraqi people since March 2003 and that violence and poor access to services are creating a public health burden of disastrous proportions.

There are other sources of information that are collected, but not released. These are the military contact reports sent every day by British and US forces, which include casualty estimates.

The US classifies this information while Britain says its figures are too unreliable to be published. Of course military contact reports do not provide a complete picture, partly because they only record deaths of Iraqis in incidents involving soldiers. But they would provide researchers with invaluable data to cross-check against other sources. The governments of both the US and UK should release the casualty figures from these reports.

Tony Blair says he is committed to protecting civilians in Iraq, as required under the Geneva conventions, but without a casualty count we have no means of knowing if he is keeping that promise.

Claims that figures are unreliable might be true if they were based on only one source. We know from our own work that a combination of methods, including hospital reports, mortuary and other official Iraqi records, coalition military data, media reporting and active data-gathering on the ground, are possible. No figures in a war zone are going to be perfect - but that's no excuse for not trying. -Dawn/The Guardian News Service.

(The writers are founders of Iraq Body Count)