NATO has rejected the conclusion of a secret US Defence Department report that the Serbs used a NATO spy to obtain secret details of bombing raids against Yugoslavia during the critical early stage of the Kosovo conflict last year.
Senior sources in the US military believe Belgrade had access to NATO's daily orders for air raids and reconnaissance flights during the first two weeks of the bombing campaign, which began on the night of March 24th, according to a BBC documentary and described in yesterday's Guardian.
But NATO's spokesman, Dr Jamie Shea, dismissed the reports, insisting there was no evidence "so far" of a leak in NATO. "If it's true that the Serbs had access to lots of juicy information about NATO's most secret operational planning and targeting, how is it that we were able to conduct, over 78 days, 38,000 sorties involving 1,200 aircraft and not lose a single pilot and only have two aircraft shot down?
"Surely if they had this information, they would have made much more effective use of it", he told BBC Radio 4.
The classified US report - which is an investigation into the lessons to be learnt from the Kosovo conflict - says the information gleaned by Belgrade enabled the Serb army and police to move soldiers and equipment around the country in advance of NATO reconnaissance missions, thus avoiding detection.
The report also says the NATO source was human and was not the result of hacking into NATO's coded computer system, Chronos, by agents acting for President Slobodan Milosevic.
Such was the sensitivity of the air tasking orders and the growing belief that they had been leaked that when US military officials discovered 600 military personnel had access to them the distribution list was quickly cut to 100.
Commenting on the reports a Downing Street spokesman said the British Prime Minister, Mr Blair, had no reason to believe there was a spy in NATO during the Kosovo conflict: "NATO themselves have said there was no spy. Had there been a spy, I think they would have heard of it.
"The bottom line speaks for itself - there were 38,000 bombing missions flown, only two aircraft down. I would have thought there might have been a slightly better hit-rate had there been a spy."
But the Shadow defence secretary, Mr Iain Duncan Smith, said the reports suggested it might be necessary in future for NATO countries to withhold sensitive military information from allies who were not militarily involved.
"This begs the question of whether it is ever feasible to operate with all the NATO nations having access to the most sensitive information, regardless as to whether they are committed in a military sense or not", he said.