The Daily Express is reporting that senior intelligence officials in the British government have confirmed that several intercepted communications between Syrian army headquarters and chemical weapons units in the field prove that the Syrian government ordered the WMD attack.

In one heated exchange, a regional commander was overheard demanding the captain of an artillery battery in a Government-held suburb of Damascus to fire chemical shells.

When the officer protested, he was told “in direct terms” that failure to comply would result in him facing a firing squad, and the chemical weapons were then fired.

The dramatic revelation, disclosed by a high-placed RAF source, came as the defiant Syrian government declared it was “fully ready” with “its finger on the trigger” for an expected US attack.

And it adds to the “evidence from thousands of sources” which US Secretary of State John Kerry has said places the chemical attacks firmly at the door of forces loyal to President Bashir Assad.

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.

Mr Kerry said at least 1,429 civilians, including 400 children, were killed in chemical attacks on 12 sites in rebel-held districts of Damascus.

He claimed: “We know that for three days before the attack, the Syrian regime’s chemical weapons personnel were on the ground in the area, making preparations.

“We know Syrian regime elements were told to prepare by putting on gas masks and taking precautions associated with chemical weapons.”

On Thursday David Cameron revealed details of British-held evidence that Assad has been behind at least 14 chemical attacks in recent weeks.

Given the Syrian opposition’s record of atrocities, it was not beyond the realm of the imagination to wonder if they had pulled off the chemical attack and then blamed it on the government. Nothing would please al-Qaeda more than to pull the US into their war and have us win it for them.

But this seems pretty conclusive. And the officer that refused the order to fire the gas shells until he was threatened with execution won’t be saved from a war crimes trial. There were many German officers during World War II who claimed that they refused to carry out orders resulting in war crimes until they were threatened with death. It didn’t wash then and it won’t wash now.

Of course, in the end it doesn’t matter that we’ve confirmed Assad is a war criminal. What matters is what we’re going to do about it. The pinprick being planned doesn’t punish anyone, or deter the regime from using gas again. So we’re back to square one; why intervene when there’s no objective, no strategy beyond the strike, and little purpose involved in risking the lives of our military?

Unless Obama can answer those questions, he won’t get his authorization to wage war.