The chief United Nations weapons inspector, Richard Butler, says tests carried out by international scientists have confirmed that Iraq filled missile warheads with the deadly nerve agent VX before the 1991 Gulf War.

In a report to the Security Council, Mr Butler says tests conducted by an American laboratory showed evidence of VX, but subsequent examinations in France and Switzerland were inconclusive.

However, the report suggests that Iraq may have tampered with the samples before the French and Swiss tests.

Baghdad has admitted that it made VX, but has always denied that it filled warheads with the agent.