BRITISH troops were sent into areas where depleted uranium ammunition had been used without being briefed about possible health risks, the Ministry of Defence conceded last night.

John Spellar, the Armed Forces minister, admitted that a training course that included instructions on how to operate in places where depleted uranium shells had exploded had been dropped last summer.

The Conservatives said they would seek an emergency statement in the Commons today. They accused the Government of displaying "complacency" towards the health of British military personnel.

In a written parliamentary answer issued last night, Mr Spellar said he had been wrong when he told the Commons in November that all troops assigned to the Balkans had been warned about the dangers of depleted uranium. "My department is now aware that not all of them have actually been briefed," he told John Swinney, of the Scottish National Party. "It has not been possible to establish how many troops have not been briefed."

He said a course on medical issues, including depleted uranium, designed for soldiers heading into theatre, had been scrapped in August last year "because of pressure on the course programme and a perception that it duplicated training". He said it had been re-instated last month, but an MoD spokesman conceded that more than 5,000 troops had been deployed in the Balkans since August and therefore may not have been trained.

The Ministry insists that depleted uranium shell residue poses a negligible risk and is dangerous to troops only if ingested in large quantities. "This is not one of the most important things that they need to be briefed on," the spokesman said. "We have robust procedures in place and everything humanly possible is done to ensure that every soldier is briefed."

Iain Duncan-Smith, the shadow defence secretary, said: "This is another example of the complacency that characterises this Government's attitude to our Armed Forces. They have put cuts first and our troops last. They deserve better. They deserve to know whether they are at risk and Parliament needs to know why we didn't get the right answer the first time."

Depleted uranium shells were used in Bosnia, Kosovo, and the Gulf War. Last month the Government gave in to public concerns and offered to screen those soldiers who feared they had been exposed.

Claims from ministers that depleted uranium shells posed no risk were undermined by reports that six Italian soldiers had died of leukaemia after coming into contact with them. Britain, along with America, rejected calls from Italy for a Nato moratorium on the use of depleted uranium shells.