In attesa del report del DNI statunitense (in relazione al quale circolano anticipazioni) possiamo leggere il sintetico assessment del Joint Intelligence Committee britannico, diffuso da qualche ora. Scrive John Day, chairman del JIC:

It is being claimed, including by the regime, that the attacks were either faked or undertaken by the Syrian Armed Opposition. We have tested this assertion using a wide range of intelligence and open sources, and invited HMG and outside experts to help us establish whether such a thing is possible. There is no credible intelligence or other evidence to substantiate the claims or the possession of CW by the opposition. The JIC has therefore concluded that there are no plausible alternative scenarios to regime responsibility.
We also have a limited but growing body of intelligence which supports the judgement that the regime was responsible for the attacks and that they were conducted to help clear the Opposition from strategic parts of Damascus. Some of this intelligence is highly sensitive but you have had access to it all.
Against that background, the JIC concluded that it is highly likely that the regime was responsible for the CW attacks on 21 August. The JIC had high confidence in all of its assessments except in relation to the regime’s precise motivation for carrying out an attack of this scale at this time – though intelligence may increase our confidence in the future.

Secondo la Reuters:

According to a former U.S. official who is an expert in the region, one possibility is that the Syrian ground commander in charge of clearing out the area which was attacked, under heavy pressure from superiors, may have made the initial decision to use chemical weapons before sending in ground troops. The official spoke on condition of anonymity.
U.S. intelligence did intercept communications discussing the attack between officials in central command and in the field. But these do not clearly implicate Assad or his entourage in ordering the use of chemicals, sources familiar with the material said.
While U.S. experts say the most likely chemical agent used in the attack was the nerve gas sarin, scientific evidence proving this still remains incomplete, one of the sources added.