The Sunday Express has a report that I consider one of the strongest pieces of evidence to date that Assad’s military was definitely behind the CW strike last week. (John Kerry is on TV citing forensic evidence, but he also said the evidence comes from someone besides the UN, which gives me pause, particularly given the way the Administration has clearly played with casualty numbers.)

According to intercepts collected at Troodos, UK’s listening post on Cyprus, the commander of the artillery unit that launched the attack balked at an order to release the CW at first, but then complied under threat of death.

Last night the senior RAF officer said: “The commander of the artillery battery told the regional commander that he would not comply and there was a heated exchange. He was told in direct language that unless the order was carried out, he would be shot. A total of 27 chemical artillery shells were then fired at the suburb in a 14-minute period.” The conversation was monitored and recorded by British officers based at the remote mountain-top RAF Troodos Signals Intelligence listening post in Cyprus and within minutes details of the conversation had been relayed to GCHQ, Whitehall and the Pentagon.

But I’m interested in the timing of this leak.

Details of this intelligence don’t show up explicitly in the British case for war, though there are claims in it that might reflect it.

There is some intelligence to suggest regime culpability in this attack. [snip] There is no obvious political or military trigger for regime use of CW on an apparently larger scale now, particularly given the current presence in Syria of the UN investigation team. Permission to authorise CW has probably been delegated by President Asad to senior regime commanders, such as [*], but any deliberate change in the scale and nature of use would require his authorisation.

However, the uncertainty as to whom Assad had delegated CW launch authority seems wholly incompatible with Whitehall having this intelligence. If they had this intercept, they would seemingly know fairly precisely the chain-of-command in question.

Nor does the intercept appear explicitly in the US case. Though again, there are claims that might reflect the intelligence.

We have intelligence that leads us to assess that Syrian chemical weapons personnel – including personnel assessed to be associated with the SSRC – were preparing chemical munitions prior to the attack. In the three days prior to the attack, we collected streams of human, signals and geospatial intelligence that reveal regime activities that we assess were associated with preparations for a chemical weapons attack. Syrian chemical weapons personnel were operating in the Damascus suburb of ‘Adra from Sunday, August 18 until early in the morning on Wednesday, August 21 near an area that the regime uses to mix chemical weapons, including sarin. On August 21, a Syrian regime element prepared for a chemical weapons attack in the Damascus area, including through the utilization of gas masks.

The one explicit mention of the content of SIGINT intercepts appears to describe the same intercept first reported by Foreign Policy.

We intercepted communications involving a senior official intimately familiar with the offensive who confirmed that chemical weapons were used by the regime on August 21 and was concerned with the U.N. inspectors obtaining evidence. On the afternoon of August 21, we have intelligence that Syrian chemical weapons personnel were directed to cease operations.

Here’s how FP reported that.

Last Wednesday, in the hours after a horrific chemical attack east of Damascus, an official at the Syrian Ministry of Defense exchanged panicked phone calls with a leader of a chemical weapons unit, demanding answers for a nerve agent strike that killed more than 1,000 people. Those conversations were overheard by U.S. intelligence services, The Cable has learned.

There are several problems with that intercept though. As FP noted, the intercept might be more consistent with a rogue commander releasing the CW as it was with an ordered strike (otherwise, why would the Ministry of Defense official be demanding panicked answers?).

A number of retired intelligence people online also noted that intercepts taken solely after the attack don’t support a premeditated attack.

And many sources suggest this was not an NSA intercept, but a Mossad one, which might not be considered reliable.

For some of those reasons, Craig Murray questioned this intercept. But he focused more on the absence — up to that point — of any news of an intercept from Troodos, which (he says) has much greater capabilities than Mossad.

It is therefore very strange, to say the least, that John Kerry claims to have access to communications intercepts of Syrian military and officials organising chemical weapons attacks, which intercepts were not available to the British Joint Intelligence Committee. On one level the explanation is simple. The intercept evidence was provided to the USA by Mossad, according to my own well placed source in the Washington intelligence community. Intelligence provided by a third party is not automatically shared with the UK, and indeed Israel specifies it should not be. But the inescapable question is this. Mossad have nothing comparable to the Troodos operation. The reported content of the conversations fits exactly with key tasking for Troodos, and would have tripped all the triggers. How can Troodos have missed this if Mossad got it?

Murray posted that yesterday morning. And then this morning, the Daily Express piece (dateline today) reports a conversation that happened last night, so after Murray raised this question.

Something else happened in the interim. The rebels complained that the US and UK had all this intelligence reflecting an impending attack but didn’t tell them.

“This is absolutely a blow to many in the opposition on the ground who’ve suffered the brunt of the chemical attacks,” said Mouaz Moustafa, executive director of the Syrian Emergency Task Force, which has long favored American intervention in the conflict. “The feeling now is that this is really an orphaned revolution and that the regime will feel emboldened to continue its shelling of cities and towns around Damascus.” [snip] Razan Zaitouneh, an anti-Assad activist in the town of Douma, one of the towns hit in the Aug. 21 attack, said she’d listened to Obama’s speech, “But [I] don’t care anymore. After learning they [the Americans] knew about the attack three days before it took place and did nothing, what should I expect from them?!” he wrote in an instant message.

When I originally read the White House case, I assumed that preliminary intelligence was inconclusive, largely reflecting the movement of equipment reported elsewhere, but had been presented in the case to be more conclusive than it really was. Which then, of course, led to the problem of seeming to make the US complicit, in its silence, in the deaths of the victims.

Which brings us back to the Express piece. Assuming the intercept really existed, here’s why the UK and US didn’t alert the rebels.

Last night senior Ministry of Defence sources confirmed that the Prime Minister was aware of several intercepts that had been picked up by nuclear submarine HMS Tireless, by RAF spy planes and by the Troodos listening station but they said the messages were initially treated with “caution” by analysts, who feared they might be fakes “planted” by rebels desperate for Western military support.

GCHQ had an intercept involving very specific people, yet judged it might be a fake planted by rebels to spur outside involvement.

On its face, the most logical takeaway here is that GCHQ did get that intercept, but it remained unmentioned in both the UK and the US case for war because the British are simply more serious about keeping secrets than the US are (unless and until Craig Murray starts asking questions). But that the understanding on the part of intelligence officials (at least within the UK) meant that they couldn’t respond to CW pre-crime intelligence because they consider the rebels so untrustworthy.

If that’s the case, it’s a telling detail.