Once or twice in a reporting lifetime, a journalist is allowed by events to participate in a project that can affect history. The film I have narrated tonight on Channel 4 – Sri Lanka’s Killing Fields – airs at 11.05 pm. It is a painful, and complex team achievement in which we have pieced together an account of what happened in the closing weeks of Sri Lanka’s civil war.

Bluntly, our evidence shows how Tamil civilians were corralled into one ever diminishing piece of land and systematically shelled and bombed by government forces. Some of the targets were medical facilities emblazoned with the internationally recognised Red Cross.

The United Nations believes at least 40,000 civilians were massacred in this process. Our evidence of how it was done comes in the form of mobile phone footage, Tamil and government film footage, and mobile phone “trophy footage” in which soldiers filmed themselves abusing and executing Tamils who had either surrendered or been captured.

War crimes were committed on both sides in what was a barbarous conflict. But the Government action that we report tonight transcends anything seen during this phase of the civil conflict.

It is a harrowing and difficult film to watch. But it represents not only the evidence required to convict, but a first ever testament in the digital age to the dawning truth that in this age it is becoming close to impossible for warring forces to cover up what they have done.

The United Nations own panel of inquiry is already satisfied that a war crime occurred on the scale and of the nature that we report tonight. Whether those responsible are brought to trial at the International Criminal Court, or at the Hague will in part depend upon the pressure from those who see this film upon their own politicians to support the ringing for charges.

Channel 4 is lifting its normal commercial access restrictions to allow the film to be freely seen by anyone anywhere in the world. Additionally, it is bound to go viral via Youtube.

This is not my normal kind of Snowblog. I end by asking you to watch this film. It could well prove a kind of a watershed, a moment when humanity, confronted with the evidence, cries ‘no more’. In our century of war – as the 21st Century is already beginning to feel – this could provide a moment when the perpetrators of war crimes meet the law courtesy of global disgust and pressure.

You will see that the film had to be, as it is, horrifically true to the facts of what happened. I hope you will spare 50 minutes tonight, it could be that it will make a difference.

@jonsnowc4

Sri Lanka’s Killing Fields will be available to watch on 4oD as soon as possible after broadcast. Channel 4 News will also be broadcasting a preview of the film during tonight’s news broadcast.

spent yesterday afternoon in the environs of the House of Commons. An extraordinary experience.

Normally, ostentatiously crawling with MPs and peers anxious to be recognised, stopped and interviewed – yesterday the place was completely deserted.

The tawdry goings-on have sent many of our legislators running for cover.

What I could not avoid was a huge demonstration on the lawn of Parliament Square – one of the biggest I have ever seen there.

For a moment I thought that the citizenry had come to the barricades to shout ‘enough’ at their MPs.

But no, this was a very unusual demonstration, and one that has been continuing for weeks.

Made up of only one ethnicity and with few others coming to their aid. They are Tamils desperately concerned about the fate of their families and friends in Sri Lanka.

I moved among them and met many. They are in many cases professionals. I met two sisters, consultants at London hospitals. I met engineers, teachers, and shop keepers.

But I also met a terrible sense of despair that we in Britain have neglected their plight and that of the one million displaced Tamils in Sri Lanka.

And I wondered, as MPs tried to wrestle the Speaker from his chair in nineteenth century scenes across the road – how fit for purpose is Parliament? What are its priorities? How far DO we respond to the foreign policy implications and sensitivities of this very sizeable minority in our midst?