Weapons expert says Syria footage 'difficult to fake'
23 August 2013 Last updated at 01:38 BST
Graphic footage of an alleged chemical weapon attack on the outskirts of Damascus has been labelled "illogical and fabricated" by the Syrian government.
The images show dozens of people being treated in make shift hospitals, suffering from - what opposition forces claim - are the effects of toxic substances launched by President Assad's forces.
The footage has promoted strong comments from the international community, with France's foreign minister stating a "reaction with force" could be needed if the the use of chemical weapons is confirmed.
The BBC's Bridget Kendall asked Stephen Johnson, an ex-chemical weapons expert with the British military, to examine a number of videos of the purported aftermath of the attack.
He said: "The consistency of the symptoms amongst hundreds of victims really seems to be quite a difficult thing to fake."