"Don't you also think that Mr Assad had "too much to lose" by using nerve gas?"

I am fairly certain that Bashar Al-Assad is under instructions from Moscow to finish this as quickly as he can - and by any means at his disposal - Saddam Hussein did not baulk at using chemical weapons when he thought he had to - so what would make Bashar al-Assad any different?

"I still think accidental detonation is the most reasonable scenario."

"Accidental detonation"?? So I see that you have swung back to it being chemical/biological armed munitions that the Free Syrian Army or one of their allied groups got their hands on and it was these that were hit in a conventional artillery barrage in Damascus on the 21st of August? Why the change back from stating that it was chemical storage cylinders that had been hit?

There are a number of drawbacks with your theory that it was chemical/biological armed munitions:

1: Those bits of kit are normally empty right up until the last possible moment.

2: Care to explain why the Free Syrian Army would bother to carry away items of military hardware that they could not possibly use? They have no Grad Rocket Launchers, they have no heavy artillery

One thing the UN weapons inspectors will have will be the dispersion pattern of the chemical agent and the limiting extent of the area affected - that will differ and indicate whether the weapon was deployed as it was designed to ("deliberate strike using chemical/biological weapons) or whether it was caused by a leak. A sympathetic detonation would destroy the chemical agent. No doubt in the course of the next few weeks we will discover which is the case.