It is difficult to express the horror and outrage we all felt at the images coming from Syria in recent day.

The reported use of chemical weapons against women, children, and other civilians has been rightly condemned by the international community. If accurate, it is a fundamental breach of international law, and the Assad regime has once again demonstrated its determined brutality. The conflict continues to spill over Syria's border with the latest figures yesterday estimating that the number of children fleeing the violence now stands at one million.

I met some of those children when I visited the Zaatari Camp on the Jordanian border. The stories they told me of their suffering live with me still. So at the G20 Summit in Russia in two weeks time, Britain's urgent priority must be to resolve the shameful underfunding of the UN's humanitarian programme. All of us feel outrage at the apparent impunity with which Bashar al-Assad has acted. The UN's Ban Ki-Moon is right to have sent his Disarmament Envoy to Damascus to urge access for the inspectors, but more could be done to back this initiative.

Sadly, the response that emerged from the United Nations on Wednesday was insufficient.

So, this weekend the British Government should initiate steps with our allies on the UN Security Council to secure the agreement of a fresh resolution that not only condemns the use of chemical weapons but also specifies the mandate of the UN inspection team already in Syria to include East Ghouta.

There is real urgency to the UN team being granted full access by the Syrian authorities to the sites of the alleged attacks. Facts and an objective analysis are vital. Evidence of the traces of toxic agents that make chemical weapons lethal can quickly be dispersed and contaminated.Those people who witnessed the appalling attack and are able to account for the absence of the signs of a conventional artillery strike must be interviewed and form part of the UN team's inquiries. To establish beyond doubt the nature, but also the perpetrators, of the strike in East Ghouta, the UN team must be granted access within days not weeks. In the hours following the emergence of the video footage, the French Foreign Minister Laurence Fabius stated that there would have to be reaction with "force" in Syria from the international community.Yet to date the Obama administration has contemplated military intervention with understandable concern.

The chairman of the US Joint Chiefs, General Martin Dempsey, in fact wrote a strikingly frank letter to the Senate Armed Forces Committee last month on the possible use of "lethal force" to stop chemical weapons proliferation in Syria.He concludes that Syria's "massive" stockpiles could only be seized or destroyed through "...a no-fly zone, as well as air and missile strikes involving hundreds of aircraft, ships, submarines" and that thousands of troops would be required on the ground.

While the international community is right to keep all its options open when dealing with a regime like Assad's, none of the military options available is without risk or potentially unforeseen consequence.As General Dempsey concluded: "Once we take action, we should be prepared for what comes next."

What is also clear is that this latest outrage - repulsive though it was - has not altered the country's trajectory towards continued conflict, crisis and possible disintegration.Nor does it strengthen the Government's case that British arms should be supplied to rebels, who include elements of Al Qaeda. Only this week General Dempsey said that no moderate rebel group was ready to fill the vacuum. The Syrian conflict is as complex as it is tragic.The scale of the human tragedy outrages us all. But, as President Obama has understood, a rash and ill-considered military intervention that inserted us into the midst of this multi-faceted conflict could actually compound rather than overcome the tragedy.