In a one-and-a-half page summary, entitled "reported chemical weapons use", John Day, chairman of the Joint Intelligence Committee (JIC), noted how it had assessed that the Syrian Government had previously used chemical weapons on 14 occasions since 2012.
This judgment was made, he explained, with the highest possible level of certainty following an exhaustive review of intelligence reports together with diplomatic and "open sources" such as video footage.
Mr Day noted there had been other attacks, although there was not the same level of confidence in the evidence. He said: "A clear pattern of regime use has, therefore, been established."
He said there was no credible intelligence to support the assertion the attacks were either faked or carried out by the Syrian rebels. "The JIC has, therefore, concluded there are no plausible alternative scenarios to regime responsibility."
The summary referred to a limited but growing body of intelligence, which supported the conclusion the Assad regime was responsible for the chemical attacks and they were conducted to help clear the rebels from strategic parts of the Syrian capital.
The JIC pointed out how it had high confidence in all of its assessments except for the Assad regime's "precise motivation" for the large-scale chemical attacks.
In the Commons, Ed Miliband, who has called for compelling evidence of the Syrian Government's culpability, made clear that, while there could always be some doubt about who was responsible, the "greater the weight of evidence the better".
Some MPs expressed concern that the JIC summary was inconclusive.
But David Cameron, in the Commons exchanges, said there was not "one smoking piece of intelligence" and it would come down to a judgment call.
The Prime Minister told MPs: "I am saying this is a judgment. We all have to reach a judgment about what happened and who was responsible.
"But all the evidence we have - the fact the opposition don't have chemical weapons, the fact the regime does, the fact they have used them, the fact they were attacking the area at the time and that intelligence that I reported - that is enough to conclude the regime is responsible and should be held accountable."
The US Government is expected to produce more evidence of the Assad regime's guilt, which is thought to include intercept communications of Syrian military chiefs discussing the chemical attack.