Russia has chalked the delay up to security concerns in Douma, which seems odd, given that foreign journalists were taken on a government-run tour of the town on Monday, when they were able to wander freely along streets close to the site of the reported attack.

When those journalists filed their reports, it became clear why Syrian and Russian officials might have preferred to give limited access to reporters rather than unfettered access to inspectors from the Organisation for the Prohibition of Chemical Weapons.