Senior former diplomats and military officials have called for an inquiry into the number of civilian deaths during hostilities in Iraq.

The move came in an open letter to the prime minister on Wednesday, as defence secretary Geoff Hoon visited British troops in Basra.

The Cabinet minister is set to meet members of the Black Watch regiment, who were controversially deployed in the American sector and have now returned to a base south of Basra.

But the trip was overshadowed by the call for the inquiry from 46 eminent figures, which also includes campaigners such as Harold Pinter and Bianca Jagger.

The move follows a study in the Lancet medical journal which claimed that as many as 100,000 Iraqis have died since the invasion.

But ministers have refused to accept the figure, claiming a more accurate and lower estimate is provided by the Baghdad Ministry of Health which reported 3,853 civilian deaths in the six months from April to October this year.

Accuracy

However the signatories to the letter said the controversy should be cleared up by an independent investigation.

"We urge you immediately to commission a comprehensive, independent inquiry to determine with the greatest possible accuracy how many Iraqis have died or been injured since March 2003," the authors said.

"As you know, your government is obliged under international humanitarian law to protect the civilian population during military operations in Iraq, and you have consistently promised to do so," the plea to Tony Blair added.

"However, without counting the dead and injured, no-one can know whether Britain and its coalition partners are meeting these obligations."

Former assistant chief of the defence staff Lord Garden said the commitment was important to show the US and UK was taking its responsibilities to Iraq seriously.

"We have taken it [Iraq] over and we are going to try and make it a democratic country," the Air Marshal told the BBC.

"We need to show the rest of the world that we are doing it in a proper, legal, moral way and one that can get the hearts and minds of the Arab and Muslim world.

"If we appear to be discarding the people there and saying they are not really important we are going to lose that battle."

Responsibility

Speaking in the Commons the prime minister disputed the claims.

"The figures from the Iraqi Ministry of Health, which are a survey of the hospitals there, are in our view the most accurate survey that there is," Tony Blair told MPs.

He added that coalition forces were trying to prevent deaths rather than cause them.

"Those people that are killing innocent people in Iraq today, who are responsible for innocent people dying, are the terrorists and insurgents who want to stop the elections happening in Iraq," he said.

"Any action that the multinational force or the Iraqi army are taking in Iraq is in order to defeat those people who are blowing up innocent people, preventing people joining the police force, killing innocent aid workers, killing anyone trying to make the country better."