Two former chiefs of the defence staff and two former commanders of UK forces in Bosnia had pledged their support for an inquiry after reports that air strikes damaged only a fraction of the Serbs' battle tanks.

Tory Defence Spokesman Iain Duncan Smith told the BBC his party supported the action over Kosovo but said some factors of the campaign had concerned them.

The BBC's Ben Brown: "There are concerns that Nato's claims were exaggerated"

"The key here is to look at what politicians said and what the outcomes were in terms of what targets were set by politicians," he said.

But defence ministers, backed by Prime Minister Tony Blair, have ruled out any inquiry into a campaign which they say achieved its aims.

Nato suspended its bombing of Yugoslavia on 10 June, the day after Belgrade agreed to a full military withdrawal from Kosovo and 11 weeks after the air campaign began.

The ruling out of ground troops has been criticised

A number of defence experts have questioned the strategy of ruling out the use of ground troops early in campaign.

Mr Duncan Smith said: "The government can't simply say, 'We are a Labour government, we are beyond approach, beyond question, whatever we say is right, there must never be a judgement made on us.'

"They must stop all this nonsense and say, 'Yes, we have nothing to hide, we think it is positive, it is a virtue we have an inquiry, let's have one now.'

"You've got ex-military chiefs saying the same, ministers in the House of Lords saying 'We don't know if we were right or wrong in the beginning.' Why don't we just have an inquiry and clear the decks."

Iain Duncan Smith: "It is time an inquiry was held"

Any inquiry would specifically look at the action taken by UK forces and decisions by UK ministers, Mr Duncan Smith said.

"We need to know because if we don't know, when it comes time to deal with Mr Milosevic again or whoever takes over there and whoever decides to destabilise the region, we will have learnt the wrong lessons.

John Spellar: "The reality is that we achieved our aims"

"We may embark on the same course of action but this time we will not be so lucky."

Defence Minister John Spellar said that after every engagement the Ministry of Defence held an internal examination.

Mr Spellar said: "The reality is we achieved our aims, we are in there now and we are actually trying to create stability in that country and also across in Bosnia, we've just picked up yet another war criminal showing the very professional job being done by our forces.

"I just find the call by the Conservatives really quite extraordinary and I would have thought they would have been supporting our forces and supporting our engagement rather than carping from the sidelines."

Military chiefs backing the Tories' call for an inquiry include the retired Field Marshall Lord Bramall and Marshall of the RAF Lord Craig.

Lieutenant General Sir Roderick Cordy-Simpson, a former United Nations chief of staff in Bosnia, also supports an inquiry.

Lieutenant General Roderick Cordy-Simpson: "We have learnt some dangerous lessons for futire conflicts"

He said: "We've just completed a hugely expensive multi-national campaign and I believe we must hold some form of inquiry, examination, after action review, call it what you like to learn the lessons.

"Clearly some things went correctly and some things did not.