A group of ex-diplomats, military men and academics has called on Tony Blair to hold an inquiry into civilian deaths in Iraq. They say the UK has a duty enshrined in international law to record the deaths.
The government thinks otherwise.
There are no official figures for the period during the war
Estimates on civilian deaths in Iraq vary from 15,000 to 100,000. But the government has no official figures.
The only organisation keeping a running total of civilian deaths in Iraq is a non-governmental group called Iraq Body Count.
On Wednesday their website said the number of civilians killed since March 2003 was between 14,619 to 16,814.
The website uses a method developed by Professor Marc Herold from the University of New Hampshire.
He recorded civilian deaths during the Afghanistan war by wading through reports from NGOs and journalists on every fatal incident.
"Thirty years ago, people used to interview victims years after the event, but this method was hopeless for Afghanistan," he said.
During that conflict populations of entire villages fled to other parts of the country, so it was impossible to track them down.
"I decided to rely on what people were saying at the time of the event, from the scene," he said.
So Prof Herold got himself "three-feet deep" in accounts of every reported fatality.
Iraq Body Count uses the same method - but with the added burden of proof that every death has to be confirmed by two independent sources.
Professor John Sloboda, part of the team behind Iraq Body Count, says the numbers are "an accurate baseline".
"There are no deaths on there that have not happened, but there may be more deaths that have not been reported," he said.
Air strikes in Falluja are thought to have killed many women and children
But the government does not accept their findings.
"This is an estimate relying on media reports, and which we do not regard as reliable," Jack Straw said in a written statement to the Commons in November.
"It includes civilian deaths at the hands of terrorists as well as of the coalition forces.
"It relies on media reporting to decide who is a civilian and who is not."
The government is similarly dismissive of a report in medical journal the Lancet which concludes that as many as 100,000 Iraqi civilians may have died.
The Lancet study is based on interviews with 988 Iraqi households in 33 randomly selected areas. Each area is meant to represent 3% of Iraq.
Their study concluded that the true body count was most likely to be around 40,000.
Military expert Paul Rogers from Bradford University believes recording civilian fatalities is vitally important from a military, as well as moral, point of view.
He said: "If you believe only 3,000 people have been killed, but the real total is closer to 20,000, then you have a false view of what is going on within the civilian population - and also what the nature and extent of any insurgency will be."
Yet neither the US nor the UK governments have collected information.
Pentagon spokesman Jim Turner said simply: "I have nothing on Iraqi civilian casualties."
The Foreign Office say they rely on figures from the Iraqi Ministry of Health.
But the ministry was only set up after the war in Iraq had come to an end - so there are no reliable figures for the war period.
Why don't the allied countries count the civilians they kill?
According to Prof Herold, the answer is simple. "They just don't care," he says.
Prof Sloboda says many believe it would be "politically embarrassing" for the government to admit that a humanitarian intervention can cause huge civilian casualties.
But the UK government says the Geneva Convention does not oblige it to record civilian loss of life - only to avoid "indiscriminate attacks" where civilians will be killed or injured.
Prof Rogers doesn't agree.
"The government might be right about the letter of the law, but not the spirit."