Radioactive dust from depleted uranium weapons remains in the atmosphere at potentially dangerous levels for up to a decade after their use.

Research by British expert Dr Chris Busby emerged as Italy's military watchdog officially linked the leukemia deaths of five Italian peacekeepers who served in Kosovo to exposure to the heavy metal.

The results of tests by Dr Busby on Gulf War battlefields contradicts advice produced by British, American and Nato defence chiefs who insist that the radioactive dust quickly disperses to safe levels, posing 'negligible risk'.

Busby's research will fuel the rapidly escalating international controversy over links between depleted uranium ammunition - used by US forces in both Bosnia and Kosovo - and claims that it has caused fatal cancers in peacekeepers who served there.

According to Dr Busby, air samples taken from Iraqi Gulf War battlefields last year, where more than 300,000 rounds of depleted uranium ammunition were used, show levels of irradiated particles in the atmosphere ten times higher than the neighbouring city of Basra and 20 times higher than Baghdad.

Iraq has long alleged that depleted uranium is responsible for abnormally high levels of childhood leukemia and birth defects following the Gulf War.

Concern over the safety of depleted uranium was reignited last month when Italy announced an investigation into 30 cases of illness involving soldiers who served in the region. Five have died from leukemia. Belgium, Spain and Portugal have also reported suspicious deaths.

The European Union has announced that it will debate the safety of depleted uranium weapons on Tuesday, further increasing pressure on Britain's Ministry of Defence which is now almost entirely isolated within Europe in resisting calls to test its Balkan veterans.

Ex-Royal Engineer Kevin Rudland has emerged as the first British case of Balkans Syndrome, claiming that he suffered a series of debilitating health problems after serving in Bosnia.

Dr Busby's claims follow the disclosure on Friday of the first results of a UN survey of uranium contamination in Kosovo. The study identified contamination at eight out of 11 sites it visited a year and a half after the end of the bombing campaign.

Despite repeated claims by the Pentagon and the MoD that debris from depleted uranium poses little risk except to those close to the immediate aftermath of their use, The Observer has established that UN civilian workers in Kosovo have been explicitly warned about the potential health risks from contamination.