and I'm confident that samples that find their way to US and UK government laboratories will also test positive.

President Bashar al-Assad appears to use chemical weapons when he is in serious trouble or bogged down in a fight. The attack at East Ghouta saved the regime, as many believe it was about to be overrun by rebels in August 2013. Extensive use of chlorine in Aleppo in December 2016 broke an almost five-year siege, and the attack last week was to try to take Idlib, which has resisted throughout the civil war. President Trump's targeting of the air base from which the Syrian Air Force jets took off was a reasonable, proportionate and effective way to re-impose a chemical weapons taboo so effectively shattered in 2013 by internationalcreated hundreds of chemical casualties.

The Russians must have been aware that the Syrian regime has been using chemical weapons, in particular chlorine barrel bombs dropped from helicopters. To not know this, when it was clear to the outside world, would be to suggest that Russian commanders are completely inept, which I highly doubt.

However, I do expect that last week's chemical attack was a surprise to the Russians. Chlorine is one thing, but sarin, many times more deadly than chlorine, is another. President Putin is no fool and would realize that the new President of the United States would be good to his word to act if the chemical red line were crossed on his watch.

After the Ghouta attack in 2013, a joint effort by the US and Russia